All About Feline Biochemistry – Complete Blood Chemistry Guide

What Is a Feline Biochemistry Test?

A feline biochemistry test is a comprehensive blood chemistry analysis that measures enzymes, proteins, electrolytes, minerals, metabolites and organ-related indicators circulating in a cat’s bloodstream. By evaluating these biochemical markers, the test provides detailed insight into the functional status of the liver, kidneys, pancreas, muscles, endocrine system, metabolic balance, electrolyte status and overall physiological health.

A feline biochemistry panel is often performed on serum obtained after blood clotting. Modern veterinary analyzers measure dozens of parameters simultaneously, allowing clinicians to detect diseases at a very early stage, sometimes long before a cat shows visible symptoms. Because cats instinctively hide signs of illness, biochemical tests are considered one of the most reliable methods for identifying abnormalities in silent or subclinical phases.

The test typically includes values such as ALT, AST, ALP, GGT, bilirubin, BUN, creatinine, glucose, cholesterol, triglycerides, calcium, phosphorus, magnesium, total protein, albumin, globulin and many others. Each parameter reflects a different organ function:

• Liver enzymes reveal hepatocellular injury or bile duct obstruction.

• Renal markers show filtration efficiency.

• Electrolytes reflect hydration and acid–base balance.

• Lipid and carbohydrate markers help identify metabolic conditions.

• Muscle enzymes demonstrate muscular or systemic damage.

In short, a feline biochemistry test is an essential diagnostic tool that evaluates internal organ health with precision and is used for screening, diagnosing, monitoring treatment progress and ensuring anesthetic safety before surgeries.

Why Is a Biochemistry Test Performed in Cats?

A biochemistry test is performed in cats to detect underlying internal disorders, assess organ function, monitor chronic disease progression and evaluate how well the body maintains metabolic stability. Because cats can mask signs of illness, this test often uncovers problems that even attentive owners may not notice.

Key Reasons for Performing the Test

1. Early Detection of Liver Disease

Enzymes such as ALT, AST, ALP, GGT and markers such as TBA reveal early hepatocellular damage, bile duct obstruction, liver inflammation, fatty liver disease and toxin exposure. Many liver conditions do not produce symptoms until advanced stages, making biochemical evaluation crucial.

2. Assessment of Kidney Function

BUN, creatinine, phosphorus and the BUN/CRE ratio identify issues such as dehydration, chronic kidney disease, acute renal injury or urinary obstruction. These markers are essential for diagnosing and staging kidney conditions.

3. Evaluation of Pancreatic Disorders

Although not fully diagnostic on their own, amylase, lipase and glucose levels help detect pancreatic inflammation, metabolic imbalances and complications related to diabetes or pancreatitis.

4. Monitoring Electrolyte and Mineral Balance

Values such as calcium, phosphorus, magnesium, tCO₂ and chloride reveal acid–base disturbances, electrolyte depletion or overload, and metabolic instability. Even mild abnormalities can affect heart rhythm, nerve conduction and muscle function.

5. Diagnosis of Metabolic and Hormonal Diseases

Diabetes mellitus, hyperthyroidism, lipid metabolism disorders and endocrine abnormalities often produce changes in glucose, triglycerides, cholesterol and other biochemical markers.

6. Detection of Toxicity and Systemic Inflammation

Certain toxins, medications, infections and inflammatory conditions elevate specific enzymes and metabolites, providing clues to systemic illness.

7. Pre-Anesthetic Evaluation

Before surgery, veterinarians must ensure the liver and kidneys can safely process anesthetic drugs. Biochemistry panels identify hidden risks and guide anesthesia planning.

8. Monitoring Chronic Illnesses and Treatments

Chronic kidney disease, liver disease, diabetes, heart disease, pancreatitis and long-term medication use all require periodic biochemical monitoring to track disease progression and adjust treatment protocols.

A feline biochemistry panel is therefore a foundational component of responsible veterinary care, allowing early detection, accurate diagnosis and effective long-term health management.

Cost of Feline Biochemistry Tests (USA, UK, EU, Türkiye Comparison)

The cost of a feline biochemistry test can vary widely depending on the country, the clinic’s diagnostic equipment, the number of parameters included in the panel and whether additional tests (CBC, electrolytes, imaging) are performed at the same visit. Although prices differ across regions, the test is considered one of the most cost-effective diagnostic tools because it can detect serious internal diseases in early stages.

Below is a detailed comparison of pricing across major regions.

United States (USA)

Veterinary costs in the US are among the highest globally, especially in urban regions such as New York, Los Angeles, San Francisco and Seattle.

Typical price ranges:

• Standard Chemistry Panel: 50 – 120 USD

• Comprehensive Panel + CBC: 120 – 250 USD

• Emergency/Acutely Ill Patient Panel: 180 – 350 USD

Prices vary depending on:

• Whether the clinic uses in-house analyzers or external laboratories

• The urgency of the case

• State-level cost differences

• The need for additional imaging (X-ray, ultrasound)

United Kingdom (UK)

The UK also has relatively high veterinary service prices.

• Basic Biochemistry Panel: 50 – 90 £

• Full Panel + Hematology: 90 – 150 £

Large corporate veterinary chains may charge significantly more, while private small clinics may be slightly cheaper. Insurance is commonly used in the UK, which helps owners manage chronic conditions.

European Union (EU)

Prices vary by country, with Northern and Western Europe being more expensive than Eastern Europe.

Typical ranges:

• Germany: 40 – 90 €

• Netherlands: 45 – 110 €

• France: 50 – 120 €

• Spain / Italy: 35 – 90 €

State-supported veterinary teaching hospitals may offer more affordable rates.

Which Factors Influence the Cost?

1. Number of parameters in the panelMore comprehensive panels include liver enzymes, renal markers, electrolytes, lipids and minerals.

2. Clinic equipment and technologyHigh-end analyzers increase accuracy but raise costs.

3. Additional diagnostic procedures

   • CBC

   • Electrolyte analysis

   • SDMA

   • Ultrasound

   • X-rayAll can add to the total cost.

4. Sedation requirementAggressive or highly stressed cats may need mild sedation for safe blood collection.

5. Emergency vs routine testingEmergency visits cost more universally.

Overall Cost Evaluation

Despite regional differences, feline biochemistry tests are among the most valuable diagnostics in veterinary medicine. They offer extensive information on internal organ function at a relatively affordable cost compared to imaging or specialized tests.

Total Protein (TP)

Total Protein (TP) represents the combined concentration of albumin and globulins in a cat’s bloodstream. These proteins are essential for maintaining oncotic pressure, supporting immune function, transporting hormones and nutrients, and preserving fluid balance within the circulatory system. Because TP reflects multiple organ systems, it is considered one of the most fundamental indicators in feline biochemistry.

What Does High Total Protein Mean?

Elevated TP levels (hyperproteinemia) can suggest:

• Dehydration – the most common cause; reduced plasma volume concentrates proteins.

• Chronic inflammation – infections, immune-mediated diseases or chronic organ disorders increase globulin production.

• Immune system activation – viral diseases (FIP, FeLV, FIV), bacterial infections or systemic inflammation.

• Neoplasia – certain cancers, such as lymphoma or multiple myeloma, can raise globulin levels dramatically.

When TP is high, the pattern of albumin and globulin levels must be examined to determine whether dehydration or true protein overproduction is responsible.

What Does Low Total Protein Mean?

Low TP (hypoproteinemia) may indicate:

• Liver failure – reduced production of albumin.

• Protein-losing nephropathy (PLN) – kidneys leak protein into the urine.

• Protein-losing enteropathy (PLE) – intestines lose protein due to inflammation or malabsorption.

• Severe malnutrition or blood loss.

Total protein always needs to be interpreted alongside albumin, globulin and the A/G ratio to fully understand the underlying cause.

Albumin (ALB)

Albumin is the most abundant protein in a cat’s serum and is produced exclusively by the liver. It plays a crucial role in maintaining vascular oncotic pressure, preventing fluid from leaking into tissues, and transporting drugs, fatty acids, hormones and calcium.

Because albumin production depends so heavily on liver function and overall protein balance, ALB is one of the most clinically meaningful markers in feline biochemistry.

High Albumin (Hyperalbuminemia)

True hyperalbuminemia is uncommon and is most often caused by:

• Dehydration – fluid loss concentrates serum proteins.

Rarely, hormonal disorders or high-protein diets may contribute, but dehydration is by far the primary reason.

Low Albumin (Hypoalbuminemia)

This finding is far more significant and may suggest:

• Liver insufficiency or liver failure – the liver cannot synthesize adequate albumin.

• Protein-losing enteropathy – chronic intestinal inflammation or malabsorption.

• Protein-losing nephropathy – kidneys leak albumin into urine.

• Chronic inflammation – albumin is downregulated while globulins increase.

• Malnutrition or cachexia – inadequate intake or severe muscle wasting.

• Severe blood loss – acute or chronic hemorrhage.

Why Albumin Is Clinically Important

Hypoalbuminemia can lead to:

• Fluid accumulation (ascites, pleural effusion)

• Peripheral edema

• Delayed healing

• Reduced drug-binding capacity

• Altered calcium values (because part of calcium is albumin-bound)

Because of these systemic effects, albumin is one of the first parameters veterinarians look at when evaluating a sick cat’s stability.

Globulin (GLO)

Globulins are a diverse group of proteins that include immunoglobulins (antibodies), acute-phase proteins and transport proteins. They play essential roles in immune defense, inflammation, nutrient transport and maintaining overall physiological stability. In a feline biochemistry panel, globulin levels provide direct insight into how actively the immune system is responding to infection, inflammation or chronic disease.

What Does High Globulin Mean?

High globulin (hyperglobulinemia) is clinically significant and often indicates:

• Chronic inflammation – prolonged immune activation raises antibody production.

• Viral diseases – especially FIP, FeLV and FIV, which strongly stimulate the immune system.

• Bacterial infections – long-standing or systemic infections.

• Immune-mediated diseases – which elevate specific globulin fractions.

• Neoplasia – especially lymphoma and multiple myeloma, which can cause very high globulin levels.

• Dehydration – can falsely elevate globulin values.

Markedly high globulin levels in cats should always trigger an evaluation for FIP, although it is not diagnostic by itself.

What Does Low Globulin Mean?

Low globulin (hypoglobulinemia) is less common but may suggest:

• Immune deficiency

• Protein-losing enteropathy

• Severe hemorrhage

• Advanced liver failure (reduced protein synthesis)

Why Globulin Matters Clinically

Globulin levels help highlight inflammatory or infectious processes long before obvious symptoms appear. Any significant deviation should be evaluated together with albumin, total protein and the A/G ratio.

A/G Ratio

The Albumin/Globulin ratio (A/G ratio) compares the amount of albumin to globulin in the bloodstream. It is an essential interpretive tool because albumin and globulins can move in opposite directions depending on the underlying disease.

A normal feline A/G ratio typically ranges from 0.6 to 1.2. Both elevations and reductions carry important diagnostic meaning.

Low A/G Ratio (Most Common Abnormality)

A low A/G ratio usually indicates:

• High globulin + low or normal albumin

• Chronic inflammation

• Infection

• Immune-mediated disease

• FIP suspicion

• Liver failure

• Protein-losing enteropathy or nephropathy

An A/G ratio below 0.5 significantly raises suspicion for conditions like FIP, although it is not confirmatory without additional testing.

High A/G Ratio

Less common and often caused by:

• Low globulin (immune suppression, protein loss)

• Severe dehydration

Why the A/G Ratio Is Important

Because the A/G ratio integrates multiple protein fractions, it is one of the most sensitive indicators of systemic disease. It helps differentiate between inflammatory, hepatic, renal and immune-mediated processes and is always interpreted alongside TP, ALB, GLO and clinical signs.

Total Bilirubin (TBIL)

Total bilirubin represents the combined amount of conjugated (direct) and unconjugated (indirect) bilirubin circulating in a cat’s bloodstream. Bilirubin is a yellow pigment produced during the normal breakdown of red blood cells. The liver processes bilirubin and excretes it into the bile ducts, eventually sending it into the intestines.

Because of this pathway, TBIL is an essential marker for evaluating red blood cell turnover, liver function and bile duct patency. Elevated bilirubin often precedes visible jaundice, making TBIL one of the earliest indicators of hepatobiliary dysfunction.

What Does High Bilirubin Mean?

High TBIL can occur for three major reasons:

1. Pre-Hepatic Causes (Hemolysis)

Red blood cells are destroyed faster than the liver can process bilirubin.Possible causes include:

• Immune-mediated hemolytic anemia

• Heinz body anemia

• Blood parasites

• Toxin exposure

• Transfusion reactions

In these cases, bilirubin builds up even though the liver is functioning normally.

2. Hepatic Causes (Liver Disease)

The liver cannot conjugate or excrete bilirubin properly.Causes include:

• Hepatic lipidosis (fatty liver)

• Toxin-induced hepatitis

• Viral hepatitis or FIP

• Liver neoplasia

• Severe inflammation or fibrosis

Hepatocellular damage reduces the liver’s ability to process bilirubin.

3. Post-Hepatic Causes (Obstruction)

Bile cannot flow into the intestines due to obstruction.Causes include:

• Gallstones

• Bile duct inflammation

• Pancreatitis causing duct compression

• Tumors blocking the bile duct

In these cases, bilirubin backs up into the bloodstream, raising TBIL levels.

Low Bilirubin

Low bilirubin is not clinically significant and is considered normal.

Clinical Importance of TBIL

Because TBIL rises in many serious conditions, it must be interpreted alongside:

• ALT, AST, ALP, GGT

• TBA (bile acids)

• Ultrasound results

• CBC (for hemolysis)

TBIL is particularly useful for identifying jaundice-type conditions before clinical symptoms appear.

AST (Aspartate Aminotransferase)

AST is an enzyme found in high concentrations in the liver, skeletal muscle, cardiac muscle and red blood cells. Unlike ALT— which is more liver-specific — AST can increase due to damage in several different tissues, making interpretation more complex.

Despite this, AST remains an essential marker for evaluating liver and muscle health, especially when interpreted together with ALT and CK (creatine kinase).

What Does High AST Mean?

1. Liver Damage

AST increases when liver cells are damaged or inflamed.Possible causes include:

• Hepatic lipidosis

• Toxin-induced liver injury

• Viral diseases such as FIP

• Bacterial hepatitis

• Liver tumors

However, AST is not liver-specific, so it must be compared to ALT.

2. Muscle Injury

Because AST is abundant in muscle tissue, it rises quickly in:

• Trauma

• Intense exercise

• Falls or vehicle injuries

• Myositis

• Hypokalemia

• Prolonged seizures

If CK is also high, the source is almost always muscular.

3. Hemolysis

If red blood cells rupture—either within the body or due to sample handling—AST may falsely elevate.

Low AST

Low AST typically has no clinical significance and is often due to normal variation or laboratory factors.

AST Interpretation

The AST/ALT relationship is critical:

• ALT > AST → More suggestive of liver injury

• AST > ALT → More suggestive of muscle damage

Always interpret AST alongside ALT, CK, bilirubin and the clinical picture to determine the true source of elevation.

ALT (Alanine Aminotransferase)

ALT is one of the most important liver-specific enzymes in cats. It is found primarily inside hepatocytes (liver cells), and when these cells are injured, inflamed or destroyed, ALT leaks into the bloodstream. For this reason, ALT is considered the most sensitive indicator of hepatocellular damage in felines.

Unlike AST, which is present in both liver and muscle tissue, ALT is highly specific to the liver. Therefore, when ALT is elevated, liver injury is far more likely than muscle injury.

What Does High ALT Mean?

ALT elevation (mild, moderate or severe) may indicate:

1. Hepatic Lipidosis (Fatty Liver Disease)

One of the most common and dramatic causes of ALT elevation in cats.ALT can rise to many times the normal range and is often accompanied by elevated bilirubin and ALP.

2. Toxin Exposure or Drug-Induced Hepatitis

Ingestion of toxic plants, chemicals, certain medications or spoiled food can damage liver cells, sharply increasing ALT levels.

3. Inflammatory or Infectious Hepatitis

Conditions such as:

• FIP

• FeLV

• FIV

• Bacterial hepatitiscan all cause ALT leakage into the bloodstream.

4. Neoplasia

Liver tumors or metastatic cancers can disrupt hepatocytes and elevate ALT.

5. Hypoxia or Severe Circulatory Problems

Shock, heart failure or severe anemia may reduce liver blood flow, causing hepatocellular injury.

Low ALT

Low ALT is not clinically meaningful.Exceptionally low ALT with severe illness may reflect end-stage liver failure where hepatocytes are too depleted to release enzymes.

Clinical Importance of ALT

Because ALT directly reflects liver-cell injury, it is always interpreted along with:

• AST

• ALP

• GGT

• Bilirubin

• TBA (bile acids)

• Ultrasound findings

ALT rises early, making it one of the most powerful early-warning markers for liver disease in cats.

AST/ALT Ratio

The AST/ALT ratio compares the level of AST to ALT and helps determine whether enzyme elevations originate from the liver or the muscle. Because cats often elevate AST due to muscle trauma, seizures or stress, this ratio is extremely helpful.

When the AST/ALT Ratio Is High (AST > ALT)

A high ratio suggests that the elevation may be muscle-related rather than liver-related.Possible causes include:

• Trauma (falls, accidents, rough handling, intense exercise)

• Myositis (muscle inflammation)

• Prolonged seizures or tremors

• Hypokalemia-induced muscle degeneration

• Injection or sampling trauma

• CK elevation (strong supportive evidence for muscle injury)

When the AST/ALT Ratio Is Low (ALT > AST)

This pattern is far more suggestive of primary liver injury.

Typical causes:

• Hepatic lipidosis

• Toxic or drug-induced hepatitis

• Infectious hepatitis

• Liver neoplasia

• Biliary obstruction

Why the AST/ALT Ratio Matters

Because AST is not liver-specific in cats, the ratio:

• Helps differentiate liver vs muscle origin

• Provides clarity when both enzymes are elevated

• Guides decisions for further testing (CK, imaging, bile acids)

Clinical Interpretation Summary

• ALT dominant elevation → liver most likely

• AST dominant elevation + high CK → muscle injury most likely

• Both high + bilirubin high → possible hepatobiliary disease

The AST/ALT ratio is one of the most important interpretive tools for veterinarians analyzing feline biochemistry panels.

GGT (Gamma-Glutamyl Transferase)

GGT is an enzyme found in the bile ducts, liver tissue and pancreas. In cats, GGT is far less reactive than in dogs, which means it does not rise easily. Because of that, when GGT is elevated in a feline biochemistry panel, it usually indicates a significant hepatobiliary abnormality, especially involving bile flow.

While ALT and AST reflect liver cell injury, GGT provides information specifically about bile duct function and cholestasis (bile flow obstruction).

What Does High GGT Mean?

1. Bile Duct Obstruction (Cholestasis)

This is the most important cause of GGT elevation in cats.Possible reasons include:

• Gallstones

• Inflammation of the bile ducts

• Pancreatitis causing compression of the bile duct

• Tumors obstructing bile flow

• Severe hepatic inflammation

GGT often increases together with ALP in obstructive conditions.

2. Hepatic Lipidosis (Fatty Liver)

Unlike dogs, cats with hepatic lipidosis may have:

• Very high ALP

• But normal or mildly elevated GGT

This ALP↑ + GGT↓ pattern is actually highly suggestive of feline fatty liver disease.

3. Drug or Toxin Exposure

Certain medications or hepatotoxic substances can increase GGT, though it is less common than ALT elevation.

Low GGT

Low or normal GGT is typical and not concerning in cats.

Clinical Interpretation of GGT

GGT is especially valuable when evaluated alongside ALP:

• ALP↑ + GGT↑ → bile duct obstruction more likely

• ALP↑ + GGT normal → hepatic lipidosis more likely

Because of its specificity, GGT helps distinguish between primary liver-cell injury and obstructive biliary problems.

ALP (Alkaline Phosphatase)

ALP is an enzyme associated with the liver, bile ducts and bone. In cats, ALP synthesis is slow and limited, meaning it does not rise easily. Therefore, an elevated ALP in a cat is always clinically meaningful and warrants careful investigation.

ALP elevation must always be interpreted with species differences in mind:

• In dogs, ALP can rise due to many benign causes.

• In cats, ALP rises only when something is significantly wrong.

What Does High ALP Mean?

1. Hepatic Lipidosis (Fatty Liver Disease)

This is the most common cause of markedly elevated ALP in cats.Typical pattern:

• ALP very high

• GGT normal or only mildly elevated

• ALT often elevated

• Bilirubin may also rise

This ALP-dominant pattern is considered characteristic of feline lipidosis.

2. Bile Duct Obstruction (Cholestasis)

Any blockage in bile flow leads to ALP elevation.Possible reasons:

• Gallstones

• Pancreatitis

• Biliary inflammation (cholangitis)

• Liver or pancreatic tumors

• Bile duct compression

In these cases both ALP and GGT usually rise together.

3. Endocrine or Metabolic Disorders

Although less common in cats, ALP can rise with:

• Hyperthyroidism

• Diabetes mellitus

• Cushing’s syndrome (rare in cats)

4. Bone Growth (Kittens)

Young kittens may have naturally higher ALP due to bone development, but this is not relevant in adult cats.

Low ALP

Normal or low ALP is typical and not clinically significant.

Clinical Interpretation of ALP

ALP must always be evaluated with:

• GGT

• ALT

• AST

• Bilirubin

• Ultrasound findings

Key feline pattern:

• ALP↑ + GGT normal → Strongly suggests hepatic lipidosis

• ALP↑ + GGT↑ → Strongly suggests bile duct obstruction

Because of these species-specific interpretations, ALP is one of the most diagnostically valuable liver enzymes in cats.

Total Bile Acids (TBA)

Total bile acids (TBA) are among the most sensitive and reliable indicators of true liver function in cats. Unlike ALT, AST, ALP or GGT—which primarily show liver damage—TBA evaluates whether the liver is still able to perform its essential metabolic duties.

Bile acids are produced in the liver, released into the intestines for digestion, reabsorbed in the gut and finally returned to the liver through enterohepatic circulation. Any disruption in this cycle—whether due to liver failure, inflammation or bile duct obstruction—causes TBA to rise.

What Does High TBA Mean?

1. Liver Functional Failure

When hepatocytes lose their ability to extract and recycle bile acids, TBA rises dramatically.This occurs in:

• Hepatic lipidosis (fatty liver disease)

• Toxic or drug-induced liver injury

• Viral hepatitis (FIP-related)

• Severe inflammation or fibrosis

• Liver tumors

Because TBA reflects functional capacity, it can be elevated even when ALT or AST are mildly abnormal.

2. Portosystemic Shunt (PSS)

A congenital or acquired abnormal vessel bypasses the liver altogether, preventing detoxification.TBA is often high before and after meals in cats with shunts.

3. Bile Duct Obstruction

If bile cannot flow into the intestine:

• Bile acids accumulate

• TBA rises sharply

This is common in pancreatitis, gallstones and biliary inflammation.

Interpreting TBA

TBA is often measured twice:

• Fasted sample

• Post-meal sample

Large increases after eating strongly support hepatobiliary disease or PSS.

Low TBA

Not clinically relevant and considered normal.

Why TBA Is Clinically Important

TBA is one of the few tests that answers:“Is the liver working properly?”Its sensitivity makes it valuable even in early or subtle liver dysfunction.

BUN (Blood Urea Nitrogen)

Blood Urea Nitrogen (BUN) measures the amount of urea in a cat’s bloodstream—a waste product formed in the liver and excreted by the kidneys. Because of this dual pathway, BUN reveals information about kidney filtration, hydration status, protein metabolism, and sometimes internal bleeding.

BUN is not specific to one organ, so interpretation must always involve creatinine, urine concentration and clinical signs.

What Does High BUN Mean?

1. Chronic Kidney Disease (Most Common Cause)

When the kidneys lose filtration capacity, urea accumulates in the blood.High BUN often accompanies:

• Increased creatinine

• High phosphorus

• Low tCO₂ (acid–base imbalance)

• Low urine concentration

2. Acute Kidney Injury

Toxins, infections, urinary blockages or sudden dehydration may raise BUN quickly.

3. Dehydration

When fluid levels drop, the kidneys concentrate urine more, causing BUN to rise.In dehydration:

• BUN rises sharply

• Creatinine often rises mildly or stays normal

• Urine concentration is high

This is why BUN/CRE ratio is essential.

4. Gastrointestinal Bleeding

Blood in the digestive tract is digested like protein → extra urea production → high BUN.

5. High-Protein Diet

Not harmful by itself, but can raise BUN temporarily.

What Does Low BUN Mean?

Less common but may signify:

• Severe liver disease (urea cannot be synthesized)

• Low-protein diet

• Overhydration or aggressive IV fluids

Clinical Importance of BUN

BUN becomes extremely valuable when combined with:

• Creatinine

• BUN/CRE ratio

• SDMA

• Urine specific gravity

• Clinical findings

Interpreted correctly, BUN helps determine whether the cat is dehydrated, in renal failure or experiencing a metabolic abnormality.

Creatinine (CRE)

Creatinine is one of the most reliable and specific indicators of kidney function in cats. It is produced at a constant rate by muscle metabolism and eliminated almost entirely through the kidneys. Because of this, creatinine levels rise only when the kidneys lose a significant portion of their filtration ability.

Unlike BUN—which can fluctuate due to dehydration, diet or bleeding—creatinine provides a clearer picture of true renal function.

What Does High Creatinine Mean?

1. Chronic Kidney Disease (CKD)

The most common cause of elevated creatinine in cats.Creatinine usually rises only after 60–70% of kidney function is lost, which makes it a strong marker for moderate to advanced CKD.

Often accompanied by:

• High BUN

• High phosphorus

• Low tCO₂

• Low urine concentration

• Elevated SDMA (earlier marker)

2. Acute Kidney Injury (AKI)

Creatinine can rise rapidly due to:

• Toxins (lilies, antifreeze, medications)

• Severe dehydration

• Urinary blockage

• Infections

• Shock or low blood pressure

AKI is a medical emergency and requires immediate intervention.

3. Dehydration

Severe dehydration may cause mild to moderate increases in creatinine, but BUN typically rises more dramatically.

4. Large Muscle Mass

Muscular cats may have slightly higher baseline creatinine levels.

What Does Low Creatinine Mean?

Usually not clinically significant.It may indicate:

• Low muscle mass (elderly or cachectic cats)

• Dilution from overhydration or IV fluids

Clinical Importance of Creatinine

Creatinine is used along with SDMA and urine concentration to stage kidney disease according to IRIS guidelines.It is essential for monitoring disease progression and guiding treatment decisions.

BUN/CRE Ratio

The BUN/CRE ratio compares Blood Urea Nitrogen to creatinine. This ratio is an essential tool for determining whether abnormalities are due to kidney dysfunction, dehydration, digestive bleeding, or metabolic disturbance.

Because BUN can rise for many reasons and creatinine is more renal-specific, the ratio helps distinguish between renal and non-renal causes.

High BUN/CRE Ratio

A high ratio commonly indicates:

1. Dehydration

The most frequent cause.BUN rises faster than creatinine because reduced plasma volume causes more urea to be reabsorbed.

2. Gastrointestinal Bleeding

Digested blood acts like extra protein intake → increases BUN disproportionately.

3. High-Protein Diet

Increases BUN without affecting creatinine.

Low BUN/CRE Ratio

A low ratio may indicate:

1. Kidney Failure

In true renal failure:

• Both BUN and creatinine rise

• But creatinine may rise relatively more → ratio decreases

2. Liver Disease

The liver produces urea, so BUN may remain low even when creatinine increases → ratio decreases.

Clinical Interpretation Summary

• High BUN + Normal CRE → Dehydration or GI bleed more likely

• Both high but CRE > BUN → Kidney disease more likely

• Low BUN + High CRE → Liver insufficiency possible

The ratio is especially valuable for answering the critical question:“Is this a kidney problem or something else?”

Creatine Kinase (CK)

Creatine Kinase (CK) is an enzyme found primarily in skeletal muscle, cardiac muscle, and to a lesser extent in the brain. It is one of the most sensitive biomarkers of muscle cell injury in cats. When muscle fibers become damaged, stressed or inflamed, CK rapidly leaks into the bloodstream, often rising much earlier and more dramatically than liver enzymes.

Because CK responds so quickly to muscle trauma, it is essential for distinguishing muscle-related enzyme elevations from liver-related ones—especially when AST is also elevated.

What Does High CK Mean?

1. Muscle Trauma (Most Common Cause)

Anything that injures muscle tissue can raise CK:

• Falls, jumps or impact injuries

• Cat fights

• Rough handling or restraint

• Transportation stress

• Injection-site muscle trauma

CK may rise several-fold within hours of injury.

2. Myositis (Muscle Inflammation)

Viral, bacterial or immune-mediated myositis can cause very high CK values.

3. Hypokalemia (Low Potassium)

Low potassium weakens muscle cells and leads to degeneration.Signs often include:

• Weakness

• Neck ventroflexion

• Tremors

CK is typically elevated alongside these symptoms.

4. Prolonged Seizures

Intense muscle contractions release large amounts of CK.

5. Toxins and Medications

Certain toxins affect muscle metabolism, causing CK to spike.

What Does Low CK Mean?

Low CK has no diagnostic value and is considered normal.

Clinical Importance of CK

CK is especially valuable when interpreted with AST and ALT:

• CK↑ + AST↑ + ALT normal → Muscle injury most likely

• CK normal + AST↑ + ALT↑ → Liver disease more likely

• CK↑ + mild ALT↑ → Mixed disorders or severe trauma

CK is one of the clearest indicators of muscle integrity in feline patients.

Amylase (AMY)

Amylase is a digestive enzyme produced mainly by the pancreas, with smaller contributions from the small intestine and liver. It helps break down carbohydrates, though cats—being obligate carnivores—naturally have lower amylase activity than dogs.

In feline medicine, amylase is not a definitive indicator of pancreatitis. However, changes in amylase values can signal disturbances in pancreatic function, kidney filtration or gastrointestinal health.

What Does High Amylase Mean?

1. Pancreatitis

Mild to moderate increases in amylase may occur in feline pancreatitis.However, cats often show normal amylase even with confirmed pancreatitis, so interpretation must be cautious.

2. Kidney Dysfunction

Because the kidneys filter amylase, reduced filtration leads to elevated amylase levels.In renal disease:

• Amylase may rise

• Lipase may rise

• Creatinine is typically elevated

• BUN is usually high

This is why renal status must be evaluated before diagnosing pancreatic disorders.

3. Gastrointestinal Diseases

Intestinal inflammation, obstruction or severe enteritis may elevate amylase.

4. Drug Effects or Toxins

Certain medications can stress the pancreas or alter enzyme metabolism.

What Does Low Amylase Mean?

Not clinically important.

Clinical Importance of Amylase

Amylase must always be interpreted with:

• Lipase

• fPL (feline pancreatic lipase immunoreactivity – the gold standard)

• Creatinine

• BUN

• Clinical signs (vomiting, abdominal pain, anorexia)

Key points:

• High amylase does not confirm pancreatitis

• Normal amylase does not rule out pancreatitis

Amylase is a supportive marker—not a standalone diagnostic tool—for pancreatic and renal evaluation.

Glucose (GLU)

Glucose is the primary energy source for nearly all cells in a cat’s body. Because it reflects the combined activity of the pancreas, liver, endocrine system, stress response, and metabolic pathways, glucose is one of the most commonly evaluated parameters in a feline biochemistry panel.

Cats are particularly sensitive to stress-induced glucose increases. Even a routine veterinary visit can cause temporary but significant hyperglycemia due to adrenaline release.

What Does High Glucose Mean?

1. Stress Hyperglycemia (Very Common in Cats)

Stress, fear, restraint, or transportation can dramatically elevate glucose levels.This rise is temporary and not a sign of disease.

2. Diabetes Mellitus

Persistent high glucose strongly suggests diabetes, especially when accompanied by:

• Excessive thirst

• Excessive urination

• Weight loss

• Increased appetite

• Glucose in urine (glucosuria)

• Ketones in urine (advanced cases)

A definitive diagnosis requires repeated glucose measurements or fructosamine testing.

3. Pancreatitis

Inflammation of the pancreas impairs insulin release and may elevate glucose.

4. Hyperthyroidism

Excess thyroid hormone increases metabolism and can push glucose upward.

5. Steroid Medications

Corticosteroids (prednisolone, dexamethasone) often raise glucose levels.

What Does Low Glucose Mean? (Hypoglycemia)

Low blood glucose can be life-threatening.

Possible causes include:

• Insulin overdose (in diabetic cats)

• Severe liver failure

• Sepsis

• Juvenile hypoglycemia (young kittens)

• Toxins

• Extreme prolonged anorexia

• Insulinoma (rare tumor)

Signs may include tremors, weakness, collapse, seizures or coma.

Clinical Interpretation

Because stress affects glucose so strongly, veterinarians often confirm abnormal readings with:

• Fructosamine

• Urine glucose/ketones

• Serial glucose tests

Glucose is critical for diagnosing endocrine disease and evaluating metabolic stability.

Cholesterol (CHOL)

Cholesterol is a vital lipid used in hormone synthesis, cell membrane structure and bile acid production. In feline biochemistry, cholesterol levels reflect important information about liver function, thyroid status, pancreatic health, and overall metabolic balance.

Unlike in humans, elevated cholesterol in cats does not usually indicate dietary issues—it is more often linked to underlying medical conditions.

What Does High Cholesterol Mean?

1. Hypothyroidism (Rare in Cats)

Although uncommon, feline hypothyroidism can significantly elevate cholesterol levels.

2. Diabetes Mellitus

Fat metabolism is impaired in diabetic cats, causing cholesterol (and triglycerides) to rise.

3. Pancreatitis

Inflammation disrupts lipid metabolism and may increase cholesterol.

4. Nephrotic Syndrome

Protein-losing kidney disease leads to marked hypercholesterolemia.

5. Liver Disease

Cholesterol can accumulate when bile production or excretion is impaired.

6. Genetic or Metabolic Disorders

Some cats have innate lipid metabolism abnormalities.

What Does Low Cholesterol Mean?

Low cholesterol may suggest:

• Severe liver failure

• Malabsorption disorders

• Starvation or extreme anorexia

• Hyperthyroidism (occasionally)

Clinical Interpretation

Cholesterol is most useful when interpreted alongside:

• Triglycerides (TG)

• ALT and ALP

• Thyroid panel (T4)

• Pancreatic tests (fPL)

Key patterns:

• CHOL↑ + TG↑ → diabetes or pancreatitis likely

• CHOL↑ + ALP↑ → hepatobiliary disease likely

• CHOL↓ + ALT↑ → possible hepatic failure

Triglycerides (TG)

Triglycerides are the primary form of stored fat in a cat’s body and serve as a major energy reservoir. They are produced in the liver, stored in adipose tissue and transported in the bloodstream. In feline biochemistry, TG levels provide important insight into lipid metabolism, pancreatic health, endocrine balance, and overall metabolic function.

An abnormal triglyceride value can indicate anything from transient dietary effects to serious metabolic disease.

What Does High Triglycerides Mean?

1. Pancreatitis

Pancreatic inflammation interferes with fat metabolism, causing TG levels to rise.A pattern of:

• TG↑ + CHOL↑ + GLU↑strengthens suspicion of pancreatitis or metabolic syndrome.

2. Diabetes Mellitus

Insulin is essential for fat regulation. Without proper insulin activity:

• Fat metabolism becomes impaired

• TG levels increase significantly

3. Hyperthyroidism (Less Common)

Thyroid hormone imbalances can disrupt lipid processing.

4. Liver Disease

The liver is central to lipid synthesis and breakdown.Fatty liver disease (hepatic lipidosis) or cholestatic disorders may elevate TG.

5. Genetic or Metabolic Disorders

Some cats naturally have higher baseline triglycerides due to genetic predisposition.

6. Corticosteroid Use

Steroid medications alter carbohydrate and fat metabolism, raising TG levels.

What Does Low Triglycerides Mean?

Not usually clinically significant.May occur with:

• Severe malnutrition

• Intestinal malabsorption

• Prolonged anorexia

Clinical Interpretation

Triglycerides are most meaningful when interpreted alongside:

• Cholesterol

• Glucose

• ALT/AST

• Pancreatic enzymes (fPL)

• Thyroid levels

TG↑ + CHOL↑ → diabetes or pancreatitis more likelyTG↑ + ALT↑ → fatty liver possible

tCO₂ (Total Carbon Dioxide)

tCO₂ reflects the total amount of carbon dioxide—primarily in the form of bicarbonate (HCO₃⁻)—present in the bloodstream. Because bicarbonate is the body’s most important buffer, tCO₂ is an essential indicator of acid–base balance and metabolic stability in cats.

Abnormal values may signal serious disturbances requiring urgent correction.

What Does High tCO₂ Mean?

A high tCO₂ level indicates metabolic alkalosis, which occurs when the blood becomes too alkaline.

Common causes include:

1. Prolonged Vomiting

Loss of stomach acid (HCl) raises bicarbonate levels.

2. Diuretics

Some medications alter electrolytes, increasing bicarbonate.

3. Hypokalemia

Low potassium shifts acid–base balance toward alkalosis.

4. Chronic Kidney Disease

Certain stages may cause bicarbonate retention.

What Does Low tCO₂ Mean?

Low tCO₂ indicates metabolic acidosis, meaning the blood has become too acidic.This is clinically more urgent and often more dangerous.

Causes include:

1. Kidney Failure

The kidneys normally eliminate acid; when they fail, acid accumulates → tCO₂ drops.

2. Diabetic Ketoacidosis (DKA)

Ketone buildup causes severe acidosis.

3. Shock or Poor Perfusion

Lactic acid accumulates when tissues lack oxygen.

4. Severe Diarrhea

Loss of bicarbonate-rich fluids lowers tCO₂.

5. Poisoning or Toxins

Some toxins induce metabolic acidosis.

Clinical Interpretation

tCO₂ is always interpreted with:

• Potassium (K)

• Chloride (Cl)

• BUN & Creatinine

• Urine pH

• Blood gas (if available)

Key patterns:

• Low tCO₂ + high creatinine → kidney failure with acidosis

• Low tCO₂ + high glucose/ketones → diabetic ketoacidosis

• High tCO₂ + low chloride → metabolic alkalosis from vomiting

tCO₂ is essential for understanding the severity of metabolic disorders.

Calcium (Ca)

Calcium is one of the most vital minerals in a cat’s body. It plays essential roles in bone health, nerve transmission, muscle contraction, blood clotting, enzyme activation and hormone regulation. Because it participates in so many physiological processes, even small abnormalities in serum calcium can indicate significant underlying disease.

Blood chemistry panels generally measure total calcium, which includes both ionized (biologically active) calcium and protein-bound calcium. When abnormalities are detected, ionized calcium testing may be necessary to determine true calcium status.

What Does High Calcium (Hypercalcemia) Mean?

Hypercalcemia is relatively uncommon in cats but is considered important when present. Causes include:

1. Cancer (Most Common Cause)

Certain cancers produce hormone-like factors that raise calcium levels:

• Lymphoma

• Squamous cell carcinoma

• Parathyroid tumors (rare but possible)

These cancers may cause severe, persistent hypercalcemia.

2. Chronic Kidney Disease

Disturbances in vitamin D metabolism, phosphorus retention and secondary hyperparathyroidism can all contribute to elevated calcium.

3. Vitamin D Toxicity

Ingestion of vitamin D–containing rodenticides or excessive supplements can cause dangerous calcium elevations.

4. Addison’s Disease (Hypoadrenocorticism)

Rare in cats but known to cause elevated calcium.

5. Granulomatous Diseases

Severe inflammation can alter vitamin D metabolism.

What Does Low Calcium (Hypocalcemia) Mean?

Hypocalcemia can be life-threatening because of its effects on the muscle and nervous systems.

Causes include:

1. Pancreatitis

Fat necrosis binds calcium, lowering serum levels.

2. Kidney Disease

Phosphorus retention and metabolic acidosis can reduce calcium.

3. Hypoparathyroidism

Failure of the parathyroid glands to regulate calcium properly.

4. Severe Systemic Inflammation or Sepsis

5. Pregnancy, Birthing or Lactation

Calcium demand increases dramatically.

Clinical Signs of Hypocalcemia

• Tremors

• Muscle twitching

• Seizures

• Weakness

• Facial rubbing

• Panting

Clinical Interpretation

Calcium should always be interpreted with:

• Albumin (because low albumin lowers total calcium)

• Phosphorus

• Kidney values (BUN, CRE)

• tCO₂

• Ionized Ca (if available)

Key patterns:

• Ca↑ + P↓ → Primary hyperparathyroidism

• Ca↓ + P↑ → Kidney failure

• Ca↓ + low albumin → check ionized calcium

Phosphorus (P)

Phosphorus is a crucial mineral involved in energy metabolism (ATP), bone structure, cellular signaling, and acid–base balance. Abnormal phosphorus values are particularly important in the diagnosis and progression of kidney disease in cats.

What Does High Phosphorus (Hyperphosphatemia) Mean?

1. Chronic Kidney Disease (Most Common Cause)

As kidney filtration declines, phosphorus accumulates.High phosphorus worsens kidney damage by triggering secondary hyperparathyroidism and mineral imbalance.

2. Hypoparathyroidism

Low parathyroid hormone reduces phosphorus excretion.

3. Vitamin D Overdose

Excess vitamin D increases both calcium and phosphorus.

4. Hemolysis

Red blood cell breakdown releases intracellular phosphorus.

What Does Low Phosphorus (Hypophosphatemia) Mean?

Causes include:

1. Hepatic Lipidosis (Fatty Liver Disease)

Cats with severe fatty liver may have dangerously low phosphorus.

2. Diabetes Treatment (Insulin Initiation)

Glucose entering cells pulls phosphorus with it → serum phosphorus drops.

3. Hyperparathyroidism

Excess PTH lowers phosphorus.

Clinical Importance of Phosphorus

Phosphorus must always be interpreted with calcium.Important patterns:

• Ca × P > 70–75 → High risk of soft tissue mineralization

• Ca↓ + P↑ → Kidney disease

• Ca↑ + P↓ → Primary hyperparathyroidism

Phosphorus is one of the most important markers for staging and managing chronic kidney disease in cats.

Calcium–Phosphorus Product (Ca × P)

The Calcium–Phosphorus Product (Ca × P) is one of the most critical indicators of mineral balance in cats, especially those with kidney disease. Instead of evaluating calcium and phosphorus separately, this calculation shows how the two minerals interact. When the product becomes too high, calcium and phosphorus begin to precipitate together, forming harmful mineral deposits in soft tissues, blood vessels, the heart and kidneys.

This makes Ca × P a vital tool in assessing both disease severity and risk of life-threatening complications.

Why Ca × P Matters

If the Ca × P value rises above certain thresholds, the cat becomes vulnerable to:

• Vascular calcification

• Mineral deposition in the kidneys

• Heart muscle mineralization

• Lung and gastric tissue calcification

• Faster progression of kidney failure

These complications are often irreversible, which is why Ca × P is closely monitored in chronic kidney disease.

Critical Thresholds

General guidelines for cats:

• Ca × P > 70–75 → High risk of soft-tissue mineralization

• Ca × P 60–70 → Warning zone; close monitoring needed

• Ca × P < 60 → Safe range

The higher the product climbs, the greater the danger.

What Causes High Ca × P?

• Chronic kidney disease (most common cause)

• Vitamin D toxicity (rodenticide ingestion or excessive supplementation)

• Primary or secondary hyperparathyroidism

• Advanced renal failure (IRIS stage 3–4)

Because phosphorus often rises in kidney disease, Ca × P can climb quickly even when calcium is only mildly elevated.

Managing a High Ca × P

• Phosphorus-restricted renal diets

• Phosphate binders

• Vitamin D modulation

• Treating underlying renal or endocrine disorders

• Regular monitoring of calcium and phosphorus

Ca × P is an essential prognostic factor for kidney health and long-term survival in feline patients.

Magnesium (Mg)

Magnesium is an essential mineral involved in more than 300 enzymatic reactions in a cat’s body. It plays a key role in muscle function, nerve conduction, electrolyte regulation, energy metabolism and cardiac stability. Although often overlooked, magnesium imbalances may signal significant metabolic or renal problems.

What Does High Magnesium (Hypermagnesemia) Mean?

High magnesium levels most commonly indicate impaired kidney function, because the kidneys are responsible for excreting excess magnesium.

Common causes:

1. Chronic Kidney Disease

Reduced filtration allows magnesium to accumulate.Often accompanied by elevated:

• Creatinine

• BUN

• Phosphorus

2. Excessive Magnesium Intake

Certain supplements, antacids or IV fluids containing magnesium may cause elevations—especially risky in cats with kidney disease.

3. Severe Tissue Injury or Breakdown

Cellular damage releases intracellular magnesium.

What Does Low Magnesium (Hypomagnesemia) Mean?

Low magnesium can dangerously affect muscle and nerve function.

Possible causes include:

1. Prolonged Vomiting or Diarrhea

Electrolyte-rich fluids are lost.

2. Diabetes Mellitus

Magnesium loss through urine is common in uncontrolled diabetes.

3. Pancreatitis

Metabolic imbalance may reduce serum magnesium.

4. Starvation or Poor Nutrition

Anorexic cats may lose magnesium reserves quickly.

Magnesium and Urinary Health

Magnesium is strongly associated with struvite urinary stones.Risk factors include:

• High dietary magnesium

• Alkaline urine

• Elevated phosphorus

For cats prone to urinary tract crystals, magnesium monitoring is essential.

Clinical Interpretation

Magnesium must be interpreted together with:

• Calcium

• Phosphorus

• Potassium

• tCO₂

• Kidney values

Even mild magnesium abnormalities can influence cardiac rhythm, muscle stability and neurological function, making Mg an important part of any feline biochemistry assessment.

FAQ – Feline Biochemistry

What is a feline biochemistry test and what does it evaluate?

A feline biochemistry test evaluates liver enzymes, kidney markers, electrolytes, minerals, proteins, metabolic waste products and pancreatic indicators. It provides a complete assessment of internal organ function and helps detect diseases long before physical symptoms appear. Because cats often hide illness, feline biochemistry is one of the most valuable diagnostic tools in feline medicine.

Why is feline biochemistry important during routine check-ups?

Even healthy-looking cats may suffer from early kidney disease, liver dysfunction or metabolic disorders. Routine feline biochemistry can detect abnormalities early, allowing treatment before irreversible damage develops. Senior cats especially benefit from yearly or semi-annual screening.

Does feline biochemistry require fasting?

Yes, most feline biochemistry panels require 8–12 hours of fasting. Food affects glucose, triglycerides, cholesterol and bile acids. However, in emergency situations the test can still be performed without fasting, with the results interpreted accordingly.

How long does it take to receive feline biochemistry results?

Most modern veterinary clinics have in-house analyzers that produce results within 15–30 minutes. Specialized tests or samples sent to external laboratories may take several hours or up to one day.

Can stress affect feline biochemistry values?

Yes. Cats are highly sensitive to stress, and adrenaline release can temporarily increase glucose levels and slightly alter other biochemical markers. This is why veterinarians may confirm abnormalities using additional tests like fructosamine or serial glucose measurements.

What liver problems can feline biochemistry identify?

Feline biochemistry can detect early liver inflammation, hepatocellular damage, bile duct obstruction, fatty liver disease, toxin exposure and viral infections such as FIP-associated hepatitis. Enzymes like ALT, AST, ALP, GGT and values like TBIL and TBA provide detailed hepatic assessment.

How does feline biochemistry detect kidney disease?

Kidney function is assessed through BUN, creatinine, phosphorus, SDMA and the BUN/CRE ratio. Elevated levels suggest reduced filtration capacity. These markers are essential for staging chronic kidney disease, diagnosing acute kidney injury and monitoring long-term progression.

Does feline biochemistry diagnose pancreatitis?

Not definitively. Amylase and sometimes lipase may increase, but feline pancreatitis often requires a specific test called fPL (feline pancreatic lipase immunoreactivity). Feline biochemistry supports the diagnosis by identifying dehydration, inflammation or metabolic imbalances.

What does an elevated ALT in feline biochemistry indicate?

An elevated ALT strongly suggests liver cell injury. Causes include hepatic lipidosis, toxin exposure, infectious hepatitis, FIP, biliary obstruction and liver tumors. ALT is one of the most sensitive indicators of hepatocellular damage in cats.

What does an elevated AST in feline biochemistry indicate?

AST elevations may originate from the liver or the muscles. Muscle trauma, seizures, hypokalemia and myositis can significantly increase AST. When AST is elevated, CK must be checked to determine whether the source is muscular or hepatic.

What does a high ALP level in feline biochemistry mean?

In cats, ALP rises only in meaningful disease processes. High ALP most commonly indicates hepatic lipidosis or biliary obstruction. ALP is especially important when interpreted together with GGT to distinguish between liver cell injury and cholestasis.

What does GGT indicate in feline biochemistry?

GGT is closely associated with bile duct health. Elevated GGT often indicates cholestasis, gallbladder disease or bile duct obstruction. The pattern of ALP↑ + GGT↑ strongly suggests obstructive biliary disease.

What does high TBA mean in feline biochemistry?

High bile acids indicate impaired liver function, such as hepatic lipidosis, severe hepatitis, portosystemic shunts or bile duct obstruction. Because TBA measures functional ability—not just enzyme leakage—it is one of the most sensitive liver tests.

What does high BUN in feline biochemistry indicate?

High BUN may indicate kidney dysfunction, dehydration, gastrointestinal bleeding or high-protein diets. BUN must always be evaluated alongside creatinine and urine concentration to determine the true cause.

What does high creatinine indicate in feline biochemistry?

Creatinine elevation is strongly associated with reduced kidney filtration. It rises in chronic kidney disease, acute kidney injury, urinary obstruction and severe dehydration. Creatinine is more kidney-specific than BUN.

What does a high BUN/CRE ratio mean in feline biochemistry?

A high BUN/CRE ratio suggests dehydration or gastrointestinal bleeding. A low ratio typically indicates true kidney failure or liver insufficiency. The ratio helps distinguish renal vs non-renal causes of abnormal values.

What does high CK indicate in feline biochemistry?

High CK indicates muscle injury, trauma, seizures, hypokalemia or myositis. When CK and AST are both increased but ALT is normal, the problem is almost always muscular rather than hepatic.

What does high amylase indicate in feline biochemistry?

High amylase may suggest pancreatitis, kidney dysfunction or gastrointestinal inflammation. However, amylase alone is not a definitive marker. It must be evaluated with fPL, lipase and renal parameters.

What does high glucose indicate in feline biochemistry?

High glucose may result from stress (very common), diabetes mellitus, hyperthyroidism, steroid medications or pancreatitis. Persistent elevation requires confirmation with fructosamine or serial glucose testing.

What does high cholesterol indicate in feline biochemistry?

High cholesterol is often associated with diabetes, pancreatitis, nephrotic syndrome or liver disorders. It rarely points to dietary issues in cats. Cholesterol becomes most meaningful when paired with triglycerides.

What does high phosphorus indicate in feline biochemistry?

High phosphorus strongly suggests chronic kidney disease. Other causes include hypoparathyroidism, vitamin D toxicity and hemolysis. High phosphorus accelerates kidney damage and requires urgent management.

Why is the Ca × P product important in feline biochemistry?

The calcium–phosphorus product predicts the risk of soft-tissue mineralization. Values above 70–75 increase the risk of vascular, kidney and heart mineral deposits. It is critical in managing chronic kidney disease.

What does high magnesium indicate in feline biochemistry?

High magnesium typically indicates reduced kidney function or excessive magnesium intake. Cats with kidney disease often accumulate magnesium because they cannot excrete it effectively.

Can feline biochemistry be normal even if a cat is sick?

Yes. Early pancreatitis, certain endocrine disorders, some viral infections and mild liver disease may appear normal on biochemistry. Additional tests such as ultrasound, CBC, urinalysis or fPL may be required.

How often should senior cats undergo feline biochemistry testing?

Senior cats (age 7+) should ideally undergo biochemistry testing every 6–12 months. Cats with chronic conditions may require testing every 3–6 months to monitor disease progression.

Sources

• American Veterinary Medical Association (AVMA)

• Merck Veterinary Manual

• Cornell University College of Veterinary Medicine

• Royal Veterinary College (RVC) – Clinical Pathology Guidelines

• Mersin Vetlife Veterinary Clinic – https://share.google/XPP6L1V6c1EnGP3Oc