Understanding Your Pet's Blood Test Results

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Why We Run Blood Tests

Blood tests are one of the most valuable diagnostic tools in veterinary medicine. They provide a snapshot of your pet's internal organ function, blood cell health, immune status, metabolic state and potential disease processes — often before obvious symptoms appear. Annual or bi-annual blood screening in healthy adults and seniors allows us to establish your pet's individual baseline and detect trends that may indicate early disease.

Complete Blood Count (CBC)

The CBC evaluates the three main cell types in blood:

• Red Blood Cells (RBCs) and Haemoglobin/Haematocrit (PCV): Low values indicate anaemia (from blood loss, bone marrow disease, chronic disease or haemolysis). Elevated values (polycythaemia) may indicate dehydration or disease.
• White Blood Cells (WBCs): Elevated counts (leucocytosis) commonly indicate infection, inflammation, stress or leukaemia. Low counts (leucopenia) suggest viral infection, bone marrow suppression or immune-mediated disease. The differential counts the types — neutrophils, lymphocytes, eosinophils (elevated in allergies/parasites) etc.
• Platelets (Thrombocytes): Low platelets (thrombocytopenia) cause spontaneous bleeding. May result from immune-mediated disease, tick-borne illness or bone marrow disease.

Biochemistry Panel — Key Values

• BUN and Creatinine: Kidney function markers. Elevated values suggest reduced kidney filtration. SDMA is a newer, more sensitive early kidney disease marker.
• ALT and AST: Liver enzymes. Elevated values indicate liver cell damage or disease.
• ALP (Alkaline Phosphatase): Elevated in liver disease, Cushing's disease (dogs) and bone disease.
• Glucose: Elevated in diabetes mellitus; low values (hypoglycaemia) in puppies, toy breeds, insulinoma or insulin overdose.
• Total Protein and Albumin: Reduced in liver disease, kidney protein loss, intestinal disease, or malnutrition.
• Electrolytes (Sodium, Potassium, Chloride): Imbalances indicate Addison's disease, vomiting/diarrhoea, kidney disease or other disorders.
• Calcium: Elevated (hypercalcaemia) in certain cancers, Addison's disease, vitamin D toxicity. Low (hypocalcaemia) in nursing females, hypoparathyroidism.
• Lipase and Amylase / cPL / fPL: Pancreatic enzymes and specific lipase tests diagnose pancreatitis.

Thyroid Testing (T4)

• Cats: Hyperthyroidism (overactive thyroid) is the most common endocrine disease in cats over 8 years. Signs: weight loss despite good appetite, vomiting, hyperactivity, increased thirst. Total T4 is the primary screening test.
• Dogs: Hypothyroidism (underactive thyroid) — weight gain, lethargy, hair loss, skin changes. Total T4 + TSH (thyroid stimulating hormone) is the screening combination.

Urinalysis

A urine sample provides complementary information to blood tests. Urine specific gravity (concentration) reflects kidney function. Protein in urine may indicate kidney disease. Glucose in urine suggests diabetes. White cells and bacteria confirm urinary tract infection. We recommend bringing a fresh morning urine sample (collected in a clean jar within 2 hours) whenever possible.

When Results Are "Borderline"

A result slightly outside the reference range is not always cause for alarm — reference ranges represent the middle 95% of healthy animals, meaning 5% of normal animals will fall outside the range. Context matters enormously: age, hydration status, stress, time since last meal and medication all affect results. This is why we assess results alongside your pet's clinical signs and history.