Dog Biochemistry – A Complete Diagnostic Guide for Canine Blood Chemistry Analysis

What Is Dog Biochemistry?

Dog biochemistry refers to the comprehensive analysis of chemical components found in a dog’s blood serum. These components include enzymes, proteins, metabolites, electrolytes, and waste products that reflect the functional health of internal organs such as the liver, kidneys, pancreas, endocrine system, and muscular system.

Unlike physical examination or imaging alone, biochemistry provides quantitative and sensitive insight into early metabolic changes long before visible clinical signs appear. For this reason, a biochemistry panel is considered one of the most essential diagnostic tools in veterinary medicine, routinely used in primary care, internal medicine, emergency cases, geriatrics, and pre-anesthetic screening.

Biochemistry testing is typically performed on a small blood sample collected after a fasting period, processed into serum, and analyzed through automated analyzers. Each parameter in the panel reflects the activity or dysfunction of a particular organ system, contributing to a complete diagnostic picture when interpreted holistically with clinical findings, hematology, and imaging results.

Purpose of Biochemistry Tests in Dogs

Biochemistry tests serve as a diagnostic backbone for evaluating organ function, metabolic stability, and systemic health. These tests are not only for detecting disease but also for monitoring recovery, guiding treatment, and preventing complications. Their purpose extends far beyond identifying abnormalities; they help veterinarians understand why a dog is symptomatic and which organ system is responsible.

Primary Purposes of Biochemistry Testing

• Assessment of liver health: ALT, AST, ALP, GGT, bilirubin, and TBA help detect hepatocellular damage, cholestasis, biliary disease, liver failure, and functional impairment.

• Evaluation of kidney function: BUN, creatinine, SDMA, electrolyte balance, and phosphorus assess both acute and chronic renal issues, filtration capacity, and metabolic waste elimination.

• Pancreatic disease detection: Amylase, lipase, triglycerides, and additional tests like cPL aid in identifying pancreatitis or pancreatic insufficiency.

• Metabolic and endocrine disorders: Glucose, cholesterol, triglycerides, and electrolyte patterns support diagnosis of diabetes mellitus, Cushing’s disease, Addison’s disease, and thyroid dysfunction.

• Electrolyte and acid–base balance: Sodium, potassium, chloride, magnesium, calcium, phosphorus, and tCO₂ reflect hydration, acid–base status, neuromuscular stability, and cardiovascular function.

• Pre-anesthetic evaluation: Ensures organs can safely metabolize anesthesia and maintain stability during surgery.

• Monitoring chronic conditions: Helps adjust long-term treatment for kidney disease, liver disease, endocrine disorders, and chronic inflammatory illnesses.

Biochemistry tests therefore play a crucial role not only in diagnostic accuracy but also in establishing prognosis and long-term management strategies.

Factors That Affect Biochemistry Values in Dogs

Biochemistry values in dogs are influenced by a combination of physiological, pathological, nutritional, medication-related, and technical factors. Understanding these influences is essential for correct interpretation of results, as abnormal values do not always indicate disease.

1. Physiological Factors

• Age: Puppies naturally have higher ALP due to bone growth; older dogs may show early kidney changes in SDMA or creatinine.

• Sex and reproductive status: Hormonal cycles may alter certain proteins or lipid values.

• Stress: Adrenaline can elevate glucose, ALP, and cholesterol.

• Exercise: CK and AST may rise temporarily after intense activity.

2. Nutritional Factors

• High-protein diets: Increase BUN and possibly creatinine.

• High-fat meals: Elevate triglycerides and lipids.

• Fasting: Lowers glucose, affects bile acids, and may alter triglycerides.

• Dehydration: Increases TP, albumin, BUN, and electrolytes.

3. Organ Dysfunction

• Liver disease: Affects ALT, AST, ALP, GGT, bilirubin, albumin, and bile acids.

• Kidney disease: Alters BUN, creatinine, SDMA, phosphorus, electrolytes.

• Pancreatic disorders: Increase amylase, lipase, triglycerides.

• Endocrine diseases: Change glucose, cholesterol, triglycerides, electrolytes.

4. Medications

Steroids, anticonvulsants, diuretics, antibiotics, anesthesia drugs, and NSAIDs can alter liver enzymes, kidney markers, and electrolytes.

5. Sample and Laboratory Factors

• Hemolysis: Raises potassium, AST, LDH.

• Lipemia: Interferes with several enzyme readings.

• Delayed processing: Lowers glucose, alters CO₂.

• Improper sampling: Can skew electrolyte values.

Because of these variables, biochemistry must always be interpreted contextually—clinical signs, physical examination, and additional tests determine the final diagnostic meaning.

TP (Total Protein)

Total Protein represents the combined concentration of albumin and globulin in a dog’s bloodstream. It is one of the most important indicators of metabolic stability, hydration status, immune activity, and organ function. Because TP incorporates two major protein groups with different physiological roles, changes in this value often reflect systemic imbalances rather than isolated organ disease.

What Causes an Increase in Total Protein?

• Dehydration: Hemoconcentration raises both albumin and globulin artificially.

• Chronic inflammation: Stimulates increased globulin production.

• Infectious diseases: Activation of the immune system elevates immunoglobulins.

• Immune-mediated disease: Overproduction of antibodies raises globulin levels.

• Certain cancers: Plasma cell tumors, lymphoma, and multiple myeloma can markedly increase globulins.

What Causes a Decrease in Total Protein?

• Liver failure: Albumin production drops since the liver synthesizes albumin.

• Protein-losing enteropathy (PLE): Chronic intestinal inflammation and lymphangiectasia cause severe protein loss.

• Protein-losing nephropathy (PLN): Kidneys lose excessive protein through the urine.

• Severe hemorrhage: Blood and plasma protein loss.

• Malnutrition or malabsorption: Inadequate dietary protein or poor intestinal absorption.

Clinical Value

TP must always be interpreted with albumin, globulin, and the A/G ratio. A high TP with low albumin suggests inflammation; a low TP with low albumin often indicates liver, kidney, or intestinal disease.

ALB (Albumin)

Albumin is the primary plasma protein produced exclusively by the liver. It maintains oncotic pressure, enabling fluid balance between blood vessels and tissues, and carries hormones, medications, fatty acids, and metabolic substances throughout the body.

What Causes Low Albumin (Hypoalbuminemia)?

• Liver insufficiency: Reduced hepatic production is a hallmark of significant liver disease.

• Protein-losing enteropathy: Chronic intestinal inflammation leads to albumin leakage.

• Protein-losing nephropathy: Glomerular disease results in albumin loss through urine.

• Chronic inflammation: The liver shifts production from albumin to immune proteins.

• Severe malnutrition or malabsorption

• Blood loss from trauma or gastrointestinal bleeding

What Causes High Albumin?

• Dehydration: Concentration of blood components elevates albumin falsely.True pathological elevations are extremely rare.

Clinical Value

Low albumin is clinically significant and may cause:

• Edema

• Ascites

• Delayed wound healing

• Muscle wasting

• Reduced drug-binding capacity

Albumin is one of the most important indicators of liver function and systemic protein balance.

GLO (Globulin)

Globulins include immunoglobulins (antibodies), acute-phase proteins, inflammatory mediators, and other immune-related proteins. Because of this, GLO is a powerful marker of immune activation, chronic inflammation, and infectious disease.

What Causes High Globulin (Hyperglobulinemia)?

• Chronic infections: Bacterial, viral, or parasitic illnesses.

• Immune-mediated diseases: Autoimmune disorders increase antibody production.

• Chronic inflammatory conditions: Prolonged inflammation stimulates protein production.

• Neoplasia: Plasma cell tumors, multiple myeloma, or lymphoma can produce excessive globulins.

What Causes Low Globulin?

• Immunosuppression (disease or medication-related)

• Protein-losing enteropathy

• Protein-losing nephropathy

• Liver dysfunction (rare but possible, as some globulins are liver-produced)

Clinical Value

Globulin should always be interpreted alongside albumin and the A/G ratio.High globulin levels strongly indicate active immune stimulation or chronic inflammation.Very high, monoclonal elevations may suggest plasma cell tumors or immune dysregulation.

A/G Ratio (Albumin / Globulin Ratio)

The A/G ratio compares albumin levels to globulin levels, making it one of the most valuable indicators of protein distribution, immune activity, and liver or intestinal function. It provides a clearer picture than evaluating albumin or globulin alone.

When Is the A/G Ratio Low?

A low A/G ratio generally means:

• Albumin is decreased

• Globulin is increased

• Or both

Most common causes:

• Chronic infections and inflammation – Increased antibody production raises globulins.

• Immune-mediated disease – Autoimmune activity elevates globulins.

• Liver failure – Albumin synthesis decreases.

• Protein-losing enteropathy – Intestinal disease causes albumin leakage.

• Protein-losing nephropathy – Glomerular damage leads to albumin loss in urine.

When Is the A/G Ratio High?

Much less common. Usually due to:

• Low globulin production

• Severe dehydration (causing disproportionately high albumin)

Clinical Value

A low A/G ratio strongly indicates immune activation, inflammation, liver dysfunction, or systemic protein loss. It is one of the most important interpretive tools in a biochemical profile, particularly when combined with TP, ALB, and GLO values.

TBIL (Total Bilirubin)

Total Bilirubin represents the total amount of bilirubin circulating in the dog’s bloodstream. Bilirubin comes from the breakdown of hemoglobin and is processed by the liver before being excreted through bile.

Abnormal TBIL levels therefore provide essential clues about:

• Hemolysis

• Liver cell damage

• Impaired bile flow

• Cholestasis

• Hepatic functional failure

Why Does Total Bilirubin Increase?

Bilirubin elevation occurs through three major mechanisms:

1. Pre-hepatic Causes (Before the Liver) – Hemolysis

• Immune-mediated hemolytic anemia

• Blood parasites (Babesia, Anaplasma)

• Toxins

• Rapid red blood cell destructionThe liver becomes overwhelmed by excess bilirubin.

2. Hepatic Causes (Inside the Liver)

• Viral, bacterial, or toxic hepatitis

• Degenerative liver disease

• Liver failure

• Drugs affecting bilirubin metabolismHere the liver cannot properly process bilirubin.

3. Post-hepatic Causes (After the Liver) – Bile Obstruction

• Gallstones or biliary sludge

• Cholecystitis (gallbladder inflammation)

• Mucoceles

• Pancreatic enlargement compressing the bile duct

• Tumors affecting the biliary treeBilirubin cannot exit the liver and backs up into the bloodstream.

Clinical Value

High TBIL often presents clinically as jaundice (yellowing of gums, sclera, skin).It must be interpreted with ALT, AST, ALP, GGT, and abdominal ultrasound for accurate diagnosis.

AST (Aspartate Aminotransferase)

AST is an enzyme found in both liver cells and muscle tissue, making it less liver-specific than ALT. Its elevation can result from hepatocellular injury, muscle damage, or hemolysis.

Why Does AST Increase?

• Liver disease: Hepatitis, toxic injury, hepatic degeneration

• Muscle injury: Trauma, strenuous exercise, seizures

• Hemolysis: Red blood cell breakdown during sampling or disease

• Pancreatitis: Mild-to-moderate increases may occur

• Certain medications can contribute to mild increases

Interpreting AST

AST is always interpreted alongside ALT:

• ALT >> AST: Primary liver cell injury

• AST >> ALT: Muscle injury or hemolysis

• ALT and AST both high: Severe liver disease or combined hepatic–muscular damage

Clinical Value

Because AST originates from multiple tissues, it requires correlation with:

• ALT

• CK (Creatine Kinase)

• Bilirubin

• Muscle history (exercise, trauma, seizures)

This combination helps distinguish liver disease from muscle-origin elevations.

ALT (Alanine Aminotransferase)

ALT is one of the most liver-specific enzymes in dogs. It is found primarily inside hepatocytes (liver cells), and any damage to these cells causes ALT to leak into the bloodstream. For this reason, ALT is a cornerstone marker for detecting and monitoring hepatocellular injury.

Why Does ALT Increase?

• Acute or chronic hepatitis

• Toxic liver injury (antifreeze, drugs, chemicals, mold toxins)

• Drug-induced liver enzyme elevation (steroids, anticonvulsants, NSAIDs)

• Hypoxia or shock affecting liver perfusion

• Hepatic lipidosis

• Trauma involving the liver

• Infections such as leptospirosis

ALT levels correlate with the degree of liver cell damage but do not always reflect liver function.

Low ALT?

Low or normal ALT is rarely clinically significant.However, in end-stage liver disease with massive hepatocyte loss, ALT may appear falsely normal due to lack of viable cells.

Clinical Value

• A mild increase may be non-specific.

• A moderate–severe increase strongly indicates hepatocellular injury.

• Very high ALT values often suggest acute or toxic liver insult.ALT must be interpreted with ALP, GGT, bilirubin, TBA, and abdominal imaging.

AST/ALT Ratio

The AST/ALT ratio helps determine whether the primary source of enzyme elevation is the liver or the muscles, since AST exists in both tissues while ALT is more liver-specific.

How to Interpret the Ratio

1. ALT > AST (Ratio < 1) – Liver Injury Most Likely

• Hepatocellular damage

• Toxic hepatopathy

• Infectious or inflammatory liver disease

This pattern indicates liver-dominant disease.

2. AST > ALT (Ratio > 1.5–2) – Muscle Injury or Hemolysis More Likely

• Muscle trauma

• Seizures

• Vigorous exercise

• Hemolytic anemia

• Myopathies

This pattern supports muscle-dominant injury.

3. AST ≈ ALT – Mixed Pattern

• Combined liver + muscle involvement

• Severe systemic illness

• Advanced metabolic stress

Clinical Value

The AST/ALT ratio is especially important when interpreting elevated AST levels.It should always be compared with CK (Creatine Kinase); if CK is also high, muscle-origin injury is strongly supported.

GGT (Gamma-Glutamyl Transferase)

GGT is a highly valuable enzyme for assessing bile duct health, biliary obstruction, and cholestasis. It is located on the membranes of bile duct cells and hepatocytes. When bile flow is impaired, GGT rises early and often significantly.

Why Does GGT Increase?

• Bile duct obstruction (gallstones, tumors, mucoceles)

• Cholecystitis (gallbladder inflammation)

• Pancreatic swelling compressing the bile duct

• Cholestasis from metabolic or hormonal disease

• Steroid-induced enzyme induction

• Biliary neoplasia

• Severe liver disease involving bile canaliculi

GGT vs ALP

GGT and ALP often rise together in biliary disease. Interpreting both simultaneously provides superior diagnostic accuracy:

• ALP ↑ and GGT ↑ → Strong evidence of cholestasis or biliary obstruction

• ALP ↑ and GGT normal → Steroid effect or bone-related ALP source

• GGT ↑ with bilirubin ↑ → High suspicion of bile duct blockage

Clinical Value

GGT is one of the best biochemical markers for distinguishing hepatocellular injury from biliary obstruction. It must be evaluated with ALP, ALT, bilirubin, and abdominal ultrasound.

ALP (Alkaline Phosphatase)

ALP is an enzyme found in the liver, bile ducts, bones, kidneys, and intestines.In dogs, ALP is particularly important because, unlike in many species, it can rise significantly due to hormonal stimulation (especially cortisol). This makes interpretation more complex and more clinically meaningful.

Why Does ALP Increase?

• Cholestasis (bile flow obstruction): Gallstones, mucoceles, biliary inflammation

• Cushing’s disease (hyperadrenocorticism): Cortisol induces ALP production

• Steroid medications: Long-term corticosteroid therapy raises ALP

• Bone growth in young dogs: Physiologic elevation, often very high

• Hepatic neoplasia: Tumors affecting the biliary tree

• Pancreatic inflammation: May mechanically compress the bile duct

Why Does ALP Decrease?

Low ALP is usually not clinically significant in dogs and often appears in normal, healthy adult animals.

Clinical Value

When ALP is evaluated together with GGT, it becomes one of the best diagnostic indicators of biliary disease:

• ALP ↑ + GGT ↑ → Strong evidence of cholestasis

• ALP ↑ + GGT normal → Steroid-induced ALP or bone-related ALP

ALP must also be compared with ALT and bilirubin for accurate interpretation.

TBA (Total Bile Acids)

Total Bile Acids (TBA) measure the liver’s functional ability rather than structural damage. Unlike ALT or AST—which indicate cell injury—TBA reflects how well the liver processes, recirculates, and clears bile acids.

Why Do Bile Acids Increase?

• Liver functional failure: Hepatitis, cirrhosis, severe hepatic lipidosis

• Portosystemic shunt (PSS): Blood bypasses the liver, preventing proper bile acid processing

• Cholestasis: Obstruction prevents bile acids from exiting the liver

• Hepatic blood flow impairment: Reduced portal circulation

• Gallbladder disease: Cholecystitis, mucoceles

Fasting and Post-Prandial Testing

TBA is usually measured:

• After fasting

• After a meal (post-prandial)

Interpretation:

• High fasting + high post-meal → Significant liver dysfunction

• Normal fasting + high post-meal → Possible portosystemic shunt

• Elevated only with bilirubin ↑ → Cholestasis very likely

Clinical Value

TBA is one of the most sensitive indicators of liver function and is essential in diagnosing liver shunts, chronic liver disease, and biliary obstruction.

BUN (Blood Urea Nitrogen)

BUN reflects the concentration of urea, a byproduct of protein metabolism produced in the liver and excreted by the kidneys. It is a major indicator of hydration, kidney function, gastrointestinal bleeding, and metabolic activity.

Why Does BUN Increase?

• Chronic kidney disease (CKD)

• Acute kidney injury (AKI)

• Dehydration: Reduced renal perfusion elevates BUN

• High-protein diet

• Upper gastrointestinal bleeding (blood digestion increases urea)

• Hypotension or shock: Decreased renal filtration

• Urinary obstruction

Why Does BUN Decrease?

• Liver failure: Decreased urea production

• Low-protein diet

• Severe malnutrition or malabsorption

• Overhydration

• Certain medications

Clinical Value

BUN must always be interpreted alongside:

• Creatinine (CRE)

• SDMA

• UrinalysisBecause BUN alone cannot differentiate between pre-renal, renal, or post-renal causes of elevation.

CRE (Creatinine)

Creatinine is a metabolic waste product derived from muscle breakdown, and it is excreted almost entirely through the kidneys. Because of this, creatinine is one of the most reliable biochemical indicators of glomerular filtration rate (GFR)—the kidneys’ ability to filter blood.

Why Does Creatinine Increase?

• Chronic Kidney Disease (CKD): Slow, progressive loss of kidney function.

• Acute Kidney Injury (AKI): Sudden damage from toxins, infection, dehydration, or urinary obstruction.

• Urinary obstruction: Bladder or urethral blockage prevents filtration.

• Severe dehydration: Reduces kidney perfusion and artificially elevates values.

• Renal toxins: Antifreeze (ethylene glycol), grapes/raisins, NSAIDs, certain antibiotics.

• Cardiac insufficiency: Reduced renal blood flow increases creatinine.

Why Does Creatinine Decrease?

• Low muscle mass (older dogs, chronic disease)

• Malnutrition

• Usually not clinically significant in isolation.

Clinical Value

Creatinine must always be interpreted with:

• BUN

• SDMA

• Urinalysis

Creatinine alone may not detect early kidney disease, but its rise—especially alongside SDMA—is a strong indicator of significant renal dysfunction.

BUN/CRE Ratio

The BUN/CRE ratio helps determine whether changes in kidney values are due to:

• Pre-renal causes (before the kidneysuch as dehydration),

• Renal causes (damage within the kidney), or

• Post-renal causes (urinary obstruction).

This ratio increases diagnostic accuracy when evaluating kidney-related abnormalities.

1. High BUN with Normal or Mildly Elevated Creatinine → Pre-Renal Causes

• Dehydration

• High-protein diets

• Internal bleeding (GI hemorrhage)

• Shock or low blood pressure

Here, kidneys themselves may be structurally normal.

2. BUN and Creatinine Both Elevated → Renal Causes

• Chronic kidney disease

• Acute kidney injury

• Renal toxins

• Kidney infections or inflammation

Indicates direct impairment of kidney tissue.

3. Severe, Abrupt Rise in Both → Post-Renal Causes

• Urethral or ureteral obstruction

• Bladder rupture (uroabdomen)

• Severe urinary retention

This is a medical emergency.

Clinical Value

The BUN/CRE ratio provides insight into the origin of kidney abnormalities and helps guide treatment. It is best interpreted alongside SDMA, urinalysis, blood pressure, and electrolyte results.

CK (Creatine Kinase)

CK is an enzyme found primarily in skeletal muscle, with smaller amounts in the heart and brain. It leaks into the bloodstream when muscle tissue is damaged.Because of this, CK is a key marker for muscle injury, inflammation, trauma, seizures, and toxin exposure.

Why Does CK Increase?

• Muscle trauma: Hit-by-car injuries, falls, crush injuries.

• Seizures: Short or prolonged seizure activity can drastically elevate CK.

• Intense exercise: Particularly in poorly conditioned dogs.

• Inflammatory myopathies: Immune-mediated or infectious.

• Toxins: Especially organophosphates and certain snake venoms.

• Ischemia: Reduced blood flow causing muscle breakdown (rhabdomyolysis).

Why Does CK Decrease?

Low CK is not clinically meaningful and usually reflects good muscle health.

Clinical Value

CK is essential for distinguishing muscle disease from liver disease when AST is elevated.

• High CK + High AST → Muscle injury

• Normal CK + High ALT/AST → Liver-origin problem

• Very high CK → Rhabdomyolysis risk

CK is also useful for monitoring recovery and determining severity of myopathies.

AMY (Amylase)

Amylase is a digestive enzyme primarily produced by the pancreas and, to a lesser extent, the small intestine. Its main function is the breakdown of dietary carbohydrates, specifically starches. In veterinary diagnostics, amylase is often considered in relation to pancreatic health, although it is not a highly specific marker on its own.

Why Does Amylase Increase?

• Acute pancreatitis: Inflammation slows enzyme movement, causing leakage into the bloodstream.

• Kidney disease: Reduced filtration leads to decreased clearance of amylase.

• Intestinal obstruction: Backflow and reduced motility increase enzyme absorption.

• Gastrointestinal inflammation: Leakage of digestive enzymes may elevate serum levels.

• Corticosteroid therapy: Can cause moderate increases.

• Trauma to abdominal organs

Why Is High Amylase Not Always Pancreatitis?

Because amylase is partially cleared through the kidneys, kidney disease can falsely elevate amylase, making it crucial to interpret with creatinine, BUN, and lipase.

Clinical Value

Amylase should never be used alone to diagnose pancreatitis.Best interpretation includes:

• Lipase levels

• cPL (canine pancreatic lipase) test

• Ultrasound examinationConsistency across these markers provides much stronger diagnostic reliability.

GLU (Glucose)

Glucose is the primary energy source for cells and an essential indicator of metabolic stability, hormonal balance, and pancreatic function. Alterations in glucose levels may reflect underlying endocrine disorders, severe systemic illness, or nutritional imbalance.

Why Does Glucose Increase? (Hyperglycemia)

• Diabetes mellitus

• Cushing’s disease (excess cortisol)

• Stress-induced hyperglycemia (common in anxious dogs at the clinic)

• Pancreatitis

• Severe infections or inflammation

• Steroid medications

• Pain, excitement, fear

Why Does Glucose Decrease? (Hypoglycemia)

• Insulinoma (pancreatic insulin-secreting tumor)

• Sepsis (bacterial toxins consume glucose)

• Liver failure (impaired gluconeogenesis)

• Puppies with low glycogen stores

• Addison’s disease

• Prolonged fasting

• Overdose of insulin

Clinical Value

Hypoglycemia is an emergency condition and may cause:

• Tremors

• Weakness

• Seizures

• Collapse

Hyperglycemia combined with increased fructosamine strongly suggests diabetes.Glucose should always be interpreted with clinical signs, urine glucose, fructosamine, cortisol, and pancreatic values.

CHOL (Cholesterol)

Cholesterol is a lipid molecule involved in hormone production, cell membrane integrity, and bile acid synthesis. Abnormal cholesterol levels often reveal underlying endocrine or metabolic diseases in dogs.

Why Does Cholesterol Increase?

• Hypothyroidism (one of the most common causes)

• Cushing’s disease

• Diabetes mellitus

• Pancreatitis

• Liver disease

• High-fat diets

• Nephrotic syndrome (protein-losing nephropathy leading to lipid elevation)

Why Does Cholesterol Decrease?

• Liver failure

• Chronic malnutrition or malabsorption

• Severe gastrointestinal disease

• Chronic infections or inflammation

Clinical Value

Cholesterol is essential in evaluating:

• Endocrine disorders (hypothyroidism, Cushing’s)

• Metabolic disease

• Nephrotic syndrome

• Pancreatic disease

Elevated cholesterol plus high triglycerides is particularly suggestive of endocrine imbalance.

TG (Triglycerides)

Triglycerides are the main form of stored fat in the body and a crucial indicator of lipid metabolism, endocrine balance, and pancreatic health. Elevated triglycerides are clinically significant in dogs because they can trigger or worsen pancreatitis, contribute to metabolic disease, and signal hormonal disorders.

Why Do Triglycerides Increase? (Hypertriglyceridemia)

• Pancreatitis: Decreased lipid clearance and enzyme leakage elevate TG levels.

• Diabetes mellitus: Poor glucose regulation disrupts fat metabolism.

• Hypothyroidism: Low thyroid hormone reduces lipid breakdown.

• Cushing’s disease: High cortisol alters lipid pathways.

• Genetic predisposition: Miniature Schnauzers are especially prone.

• Obesity: Excess adipose tissue elevates circulating lipids.

• High-fat diets: Directly elevate triglycerides.

Why Do Triglycerides Decrease?

Typically less clinically significant; often associated with:

• Prolonged fasting

• Malnutrition

• Chronic gastrointestinal disease affecting absorption

Clinical Value

• TG ↑ + Cholesterol ↑ → Strong suspicion of endocrine/metabolic disorders

• Very high TG → Increased risk of acute pancreatitisMonitoring triglycerides is essential in dogs with endocrine disease, pancreatitis history, or genetic susceptibility.

tCO₂ (Total Carbon Dioxide)

Total CO₂ reflects the concentration of bicarbonate (HCO₃⁻) and dissolved carbon dioxide in the bloodstream, making it a key indicator of acid–base balance.Abnormal tCO₂ values reveal whether a dog is experiencing metabolic acidosis or alkalosis—both potentially life-threatening conditions.

Why Does tCO₂ Increase? (Metabolic Alkalosis)

• Severe or prolonged vomiting (loss of stomach acid)

• Use of certain diuretics

• Hypokalemia (low potassium alters renal bicarbonate handling)

• Excessive bicarbonate administration

Why Does tCO₂ Decrease? (Metabolic Acidosis)

• Chronic or acute kidney disease (bicarbonate loss)

• Diabetic ketoacidosis (DKA)

• Sepsis or severe infection

• Toxin exposure (ethylene glycol, aspirin overdose)

• Severe diarrhea (loss of bicarbonate in stool)

• Lactic acidosis from shock or poor perfusion

Clinical Value

Low tCO₂ is more common and represents metabolic acidosis, which requires IMMEDIATE attention.Interpreting tCO₂ requires correlation with:

• Electrolytes (especially Cl⁻ and K⁺)

• Blood pH (via blood gas analysis)

• Kidney values (BUN, CRE)

tCO₂ is essential in diagnosing and grading acid–base disturbances.

Ca (Calcium)

Calcium is vital for muscle contraction, nerve transmission, blood clotting, bone strength, hormone regulation, and overall metabolic stability. Because it influences so many systems, abnormalities in calcium can produce severe clinical signs.

Why Does Calcium Increase? (Hypercalcemia)

• Cancer: Lymphoma, anal sac adenocarcinoma (most common cause)

• Addison’s disease

• Kidney disease

• Vitamin D toxicity

• Primary hyperparathyroidism

• Granulomatous inflammation

• Bone tumors or bone destruction

Hypercalcemia can quickly become a medical emergency, leading to kidney damage, heart rhythm disturbances, and neurological signs.

Why Does Calcium Decrease? (Hypocalcemia)

• Eclampsia (postpartum hypocalcemia)

• Hypoparathyroidism

• Pancreatitis

• Kidney failure

• Sepsis

• Massive blood transfusion (citrate binding)

• Severe hypoalbuminemia (total Ca appears low despite normal ionized Ca)

Clinical Value

Because total calcium includes protein-bound calcium, it must be interpreted alongside:

• Ionized calcium (iCa)

• Albumin

• Phosphorus (P)

• Ca × P ratio

Clinical signs of calcium imbalance include tremors, arrhythmias, seizures, weakness, vomiting, and kidney injury.

P (Phosphorus)

Phosphorus is an essential mineral involved in cellular energy production (ATP), bone mineralization, acid–base balance, and metabolic function. In dogs, phosphorus levels are tightly regulated by the kidneys, parathyroid hormone (PTH), and vitamin D. Therefore, changes in phosphorus are often linked to kidney disease, endocrine disorders, or nutritional imbalances.

Why Does Phosphorus Increase? (Hyperphosphatemia)

• Chronic Kidney Disease (CKD): The most common cause; impaired filtration leads to phosphorus retention.

• Acute Kidney Injury: Kidney shutdown prevents excretion.

• Low calcium / high phosphorus diets

• Vitamin D toxicity

• Tumor lysis syndrome

• Hypoparathyroidism

• Metabolic acidosis

High phosphorus is a key driver of secondary renal hyperparathyroidism, a condition that accelerates kidney damage.

Why Does Phosphorus Decrease? (Hypophosphatemia)

• Prolonged malnutrition or starvation

• Malabsorption disorders

• Refeeding syndrome

• Insulin overdose (drives phosphorus into cells)

• Chronic vomiting or diarrhea

Clinical Value

Phosphorus must always be interpreted alongside calcium and kidney values (BUN, CRE, SDMA).High phosphorus, especially when paired with high Ca × P ratios, significantly worsens renal prognosis.

Ca × P Ratio

The Ca × P ratio (calcium multiplied by phosphorus) is one of the most important calculations in evaluating kidney disease severity, mineral imbalance, and risk of soft-tissue calcification.

This ratio is used extensively in internal medicine because abnormal Ca × P levels predict vascular calcification, tissue mineralization, and mortality risk in dogs with kidney disease.

Interpretation

• Ca × P < 60: Generally safe and physiologically normal.

• Ca × P 60–70: Borderline; monitor closely.

• Ca × P > 70: High risk of soft tissue mineralization, vascular calcification, and rapid CKD progression.

• Ca × P > 90: Severe risk; urgent medical intervention required.

Why Does the Ratio Increase?

• High phosphorus from CKD

• Hypercalcemia

• Vitamin D toxicity

• Hormonal disorders

• Unbalanced mineral supplementation

Clinical Value

A persistently high Ca × P ratio indicates that the dog’s mineral regulation system is failing, often due to kidney disease or endocrine problems. It is essential for long-term management and dietary planning in renal patients.

Mg (Magnesium)

Magnesium is a critical mineral involved in nerve conduction, muscle contraction, cardiac rhythm regulation, enzyme function, and electrolyte balance. Even minor deviations in magnesium levels can disrupt neuromuscular stability.

Why Does Magnesium Increase? (Hypermagnesemia)

• Kidney failure: Primary cause; the kidneys fail to excrete magnesium.

• Addison’s disease

• Severe tissue breakdown (rhabdomyolysis)

• Over-supplementation

• Certain medicationsMagnesium excess depresses neuromuscular and cardiac function.

Why Does Magnesium Decrease? (Hypomagnesemia)

• Chronic diarrhea or vomiting

• Intestinal malabsorption

• Diuretics (particularly loop diuretics)

• Pancreatitis

• Prolonged malnutrition

• Diabetes mellitusLow magnesium often accompanies low potassium and low calcium.

Clinical Value

• Low Mg: Tremors, twitching, arrhythmias, seizures

• High Mg: Weakness, lethargy, slow heart rate, respiratory depression

Magnesium supports potassium and calcium stability, making it essential in interpreting electrolyte imbalances.

FAQ – Frequently Asked Questions About Dog Biochemistry

What does a biochemistry test actually reveal about my dog’s health?

A biochemistry test analyzes enzymes, proteins, electrolytes, metabolites, and waste products in your dog’s bloodstream. These values indicate how well vital organs—such as the liver, kidneys, pancreas, endocrine system, and muscles—are functioning. Biochemistry can detect disease long before physical symptoms appear. Tests like ALT and AST show liver cell damage, BUN and creatinine measure kidney filtration, glucose and lipids assess metabolic balance, while electrolytes reveal hydration and acid–base status. It is one of the most comprehensive diagnostic tools in veterinary medicine.

Does an abnormal biochemistry value always mean my dog is sick?

Not necessarily. Some values may change due to normal physiological variations. Puppies have naturally higher ALP due to bone growth, stress can temporarily raise glucose and ALP, strenuous exercise can increase CK, and dehydration can make total protein and albumin appear higher. This is why biochemistry must always be interpreted in context with clinical signs, physical examination, and sometimes additional imaging or tests.

Should my dog fast before a biochemistry test?

Yes. Dogs should typically fast for 8–12 hours before blood collection. Food intake can artificially elevate glucose, triglycerides, and bile acids, leading to misleading results. Water is allowed. If the dog is on medications, always inform the veterinarian since some drugs can affect liver and kidney values.

Can biochemistry tests detect liver disease early?

Yes. Liver disease is one of the first conditions biochemistry can detect. ALT and AST show hepatocyte injury, ALP and GGT reflect cholestasis or bile duct obstruction, bilirubin increases with impaired bile flow, and Total Bile Acids (TBA) reveal decreased liver functional capacity. Many dogs show no outward symptoms until disease is advanced, making biochemistry essential for early detection.

Which biochemistry values indicate kidney disease?

Kidney disease is usually reflected by elevations in BUN, creatinine, and SDMA, along with changes in phosphorus and electrolytes. SDMA is especially important because it rises earlier than creatinine, detecting kidney dysfunction in its early stages. Advanced kidney problems may also cause metabolic acidosis, low tCO₂, high potassium, anemia, and dehydration.

Does biochemistry alone diagnose pancreatitis?

Biochemistry provides important clues—amylase, lipase, and triglycerides often rise—but these are not sufficient for a definitive diagnosis. The most reliable test for pancreatitis is cPL (canine pancreatic lipase). Ultrasound is also very helpful. Biochemistry mainly helps assess the severity of dehydration, electrolyte disturbances, and organ involvement.

Can stress affect my dog’s biochemistry results?

Yes. Stress can significantly elevate glucose, cholesterol, and ALP due to hormone release (adrenaline and cortisol). Nervous or anxious dogs may show mild biochemical changes that do not necessarily indicate disease. In borderline cases, repeat testing may be recommended.

How dangerous are electrolyte abnormalities in dogs?

Electrolyte imbalances can be life-threatening. High potassium can cause fatal heart rhythm disturbances. Extreme sodium changes can cause brain swelling or shrinkage, leading to seizures or coma. Abnormal calcium can cause tremors, arrhythmias, kidney damage, or seizures. Electrolytes are some of the most critical values in emergency care.

How often should my dog get a biochemistry panel?

Healthy adult dogs generally need a biochemistry test once a year.However, dogs with chronic disease—kidney, liver, pancreas, endocrine disorders—or dogs on long-term medications should be tested every 1–3 months. Senior dogs benefit from more frequent monitoring (2–3 times per year).

Can a biochemistry profile detect poisoning or toxin exposure?

Yes. Several toxins cause rapid changes in ALT, AST, BUN, creatinine, electrolytes, and glucose. Antifreeze poisoning, grape/raisin toxicity, xylitol poisoning, rodenticide ingestion, and heavy metals often cause dramatic organ enzyme shifts that biochemistry reveals early.

Why might an ultrasound be recommended after abnormal biochemistry results?

Biochemistry identifies which organ is affected, while ultrasound identifies why it’s affected. For example:

• High ALP + GGT → ultrasound checks for gallbladder disease

• High BUN/creatinine → ultrasound evaluates kidney structure

• High bilirubin → ultrasound checks bile duct obstructionThe combination gives a complete diagnostic picture.

Can my dog have normal biochemistry and still be sick?

Yes. Early stages of many diseases may not yet reflect biochemical changes.Examples include:

• Early pancreatitis

• Mild kidney dysfunction (before SDMA rises)

• Early Addison's disease

• Hormonal imbalances

• Mild inflammatory liver diseaseThis is why veterinarians consider history, symptoms, physical examination, and multiple diagnostic tools together.

What symptoms can low albumin cause in dogs?

Albumin helps maintain fluid balance. When it drops, fluid leaks into tissues.Symptoms may include:

• Edema (swelling of limbs)

• Ascites (fluid in the abdomen)

• Muscle wasting

• Weakness

• Slow wound healing

• Poor drug metabolismLow albumin is a serious finding, especially when caused by liver disease or intestinal/bone marrow disorders.

What does it mean when BUN is high but creatinine is normal?

This pattern typically suggests pre-renal factors, not intrinsic kidney disease.Possible causes include:

• Dehydration

• High-protein diet

• Gastrointestinal bleeding

• Shock or low blood pressureThe kidneys themselves may function normally, but blood supply or protein metabolism is altered.

Is high creatinine always kidney failure?

No. While kidney failure is the most common cause, creatinine can also rise due to:

• Dehydration

• Urinary obstruction

• Muscle breakdown

• Certain medications

• ShockTherefore, creatinine should be assessed with SDMA, BUN, electrolytes, and urinalysis.

Why are bile acids (TBA) important if ALT and AST are already high?

ALT and AST show cell damage, but TBA shows liver function.A dog may have high ALT/AST but still retain normal functional capacity.TBA identifies functional impairment, portosystemic shunts, and early liver failure that enzyme elevations alone cannot detect.

Why is hypercalcemia (high calcium) dangerous for dogs?

Elevated calcium can:

• Damage kidneys

• Cause arrhythmias

• Lead to muscle tremors

• Cause vomiting and dehydration

• Trigger neurological signsIt is commonly associated with cancers, Addison’s disease, and vitamin D toxicity.

Which biochemistry abnormalities indicate an emergency?

• K⁺ severely high → risk of cardiac arrest

• Sodium dangerously low or high → seizures, coma

• Very high phosphorus + high Ca × P ratio → renal mineralization

• Massively elevated bilirubin → bile duct obstruction

• Sky-high CK → rhabdomyolysis

• Severe hypoglycemia → seizures/collapseThese findings require immediate veterinary intervention.

Sources

• American Veterinary Medical Association (AVMA)

• Merck Veterinary Manual

• Cornell University College of Veterinary Medicine

• Royal Veterinary College – Clinical Pathology Guidelines

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