Describe the various blood biochemical tests and discuss their importance in health status of animals.

Hematological Parameters and Their Significance

Hematology focuses on the cellular components of blood. These tests are crucial for assessing red blood cell function, white blood cell response to infection, and platelet function.

• Complete Blood Count (CBC): Measures red blood cell count (RBC), hemoglobin (Hb), hematocrit (Hct), white blood cell count (WBC), and platelet count. Deviations from normal ranges can indicate anemia, infection, inflammation, or bleeding disorders. For example, a high WBC count often suggests infection or inflammation.
• Packed Cell Volume (PCV): Reflects the percentage of red blood cells in the total blood volume. Low PCV indicates anemia, while high PCV can be due to dehydration or polycythemia.
• Red Blood Cell Indices: Mean Corpuscular Volume (MCV), Mean Corpuscular Hemoglobin (MCH), and Mean Corpuscular Hemoglobin Concentration (MCHC) provide information about the size and hemoglobin content of red blood cells, helping differentiate types of anemia.

Biochemical Tests: Assessing Organ Function

Biochemical tests evaluate the levels of various enzymes, proteins, and metabolites in the blood, offering a window into the health of different organ systems.

Liver Function Tests (LFTs)

• Alanine Aminotransferase (ALT) & Aspartate Aminotransferase (AST): Elevated levels indicate liver cell damage. ALT is more specific to the liver than AST.
• Bilirubin (Total & Direct): Elevated levels suggest impaired bilirubin metabolism, potentially due to liver disease or biliary obstruction.
• Alkaline Phosphatase (ALP): Can indicate liver or bone disease. In young, growing animals, elevated ALP may be due to bone growth.
• Albumin & Total Protein: Decreased levels can signify liver disease, malnutrition, or protein loss.

Kidney Function Tests (KFTs)

• Blood Urea Nitrogen (BUN): Elevated levels indicate impaired kidney function or dehydration.
• Creatinine: A more specific indicator of kidney function than BUN. Increased levels suggest kidney damage.
• Phosphorus: Abnormal levels can indicate kidney dysfunction.

Electrolyte Imbalances

• Sodium, Potassium, Chloride: These electrolytes play crucial roles in maintaining fluid balance, nerve function, and muscle contraction. Imbalances can result from various diseases or medication effects.

Other Important Biochemical Tests

• Glucose: Monitors carbohydrate metabolism. High glucose indicates diabetes mellitus; low glucose indicates hypoglycemia.
• Calcium: Important for bone health, muscle function, and nerve transmission. Abnormal levels can indicate parathyroid disorders or kidney disease.
• Lipid Profile (Cholesterol, Triglycerides): Assesses cardiovascular health.

Endocrine Tests

These tests evaluate hormone levels, crucial for diagnosing endocrine disorders.

• Thyroid Hormone (T4): Assesses thyroid gland function.
• Cortisol: Measures adrenal gland function.

Test	What it Measures	Significance in Animal Health
ALT	Liver enzyme	Indicates liver cell damage
BUN	Waste product	Indicates kidney function or dehydration
Glucose	Sugar level	Indicates diabetes or hypoglycemia
CBC	Cellular components of blood	Detects anemia, infection, inflammation

Importance in Health Status

Biochemical tests are critical for:

• Disease Diagnosis: Identifying the underlying cause of clinical signs.
• Monitoring Disease Progression: Tracking the effectiveness of treatment and adjusting therapies as needed.
• Preventative Healthcare: Identifying early signs of disease before clinical signs develop. This is particularly important in older animals.
• Pre-Anesthetic Screening: Assessing organ function before surgical procedures.

A young Labrador Retriever presents with vomiting and diarrhea. Blood biochemical tests reveal elevated ALT and bilirubin, suggesting liver dysfunction. Further investigation reveals hepatic lipidosis, a condition often associated with rapid weight gain followed by starvation. Case Study: Chronic Kidney Disease in a Senior Cat A 14-year-old Persian cat exhibited lethargy and decreased appetite. Blood tests revealed elevated BUN and creatinine, indicating chronic kidney disease (CKD). The cat was placed on a renal diet and given subcutaneous fluids. Serial biochemical tests were used to monitor the progression of the disease and adjust treatment accordingly.