Veterinary Serum Biochemistry: Tests, Sample Collection, and Interpretation

What types of tubes are used for serum biochemistry?

Serum (plain), serum gel, OXF (yellow-topped), and EDTA (pink, red, or purple-topped) tubes.

Which tube is used for haematology analysis?

EDTA tube.

What is the primary use of the OXF tube?

To measure glucose.

What type of tube is used for clotting factor tests?

Citrate (green-topped) tube.

What is the significance of serum quality during testing?

It can significantly affect the accuracy of the results.

What are the four categories of serum quality?

Normal, lipaemic, haemolysis, and icteric.

Describe normal serum quality.

Clear to straw-coloured.

What causes lipaemic serum?

The presence of fat (triglycerides and cholesterol) leading to a milky appearance.

What is haemolysis and what causes it?

The serum turns pink to red due to the loss of haemoglobin from red blood cells, often caused by trauma during handling or medical conditions.

What does icteric serum indicate?

Various shades of yellow due to the build-up of bilirubin, often seen in liver disease.

What is ALT and its significance in liver function?

Alanine aminotransferase is liver-specific in dogs and cats; elevated levels indicate hepatocellular damage.

What conditions can cause elevated ALT levels?

Hepatitis, tumours, hyperthyroidism (in cats), and trauma.

What does ALKP stand for and what does it indicate?

Alkaline phosphatase; elevations indicate liver and bile duct release or bone growth.

What conditions can elevate ALKP levels?

Liver disease, Cushing's disease, steroid therapy, and anti-epileptic drug therapy.

What is bilirubin and what does it indicate?

A yellow pigment produced from the breakdown of red blood cells; elevated levels indicate jaundice.

What causes increased bilirubin levels?

Increased breakdown of red blood cells, hepatocellular damage, or bile flow obstruction.

What are bile acids and their function?

Synthetized in the liver, they act as emulsifying agents during fat digestion and indicate liver function.

What can cause increased bile acid levels?

Impaired liver function, biliary obstruction, or a porto-systemic shunt.

What is amylase and its primary source?

A digestive enzyme mainly from the pancreas, liver, and small intestine.

What conditions can cause elevated serum amylase levels?

Pancreatitis and renal disease.

What is lipase and its significance?

A digestive enzyme primarily from the pancreas; elevated levels indicate pancreatitis.

What can affect amylase and lipase levels in serum samples?

Grossly haemolysed and lipaemic samples can artificially alter the results.

What is urea and how is it formed?

Formed in the liver from the breakdown of ammonia and excreted through the kidneys in urine.

What are the three categories of elevated urea levels?

Pre-renal, renal, and post-renal.

What causes pre-renal elevations in urea?

Tissue necrosis, fever, infection, steroid therapy, dehydration, and intestinal bleeding.

When do renal elevations in urea occur?

When 75 percent of the nephrons become non-functional.

What is a common issue that leads to post-renal elevations in urea?

Obstruction in the flow of urine, such as a blocked bladder in cats.

What is azotaemia?

An increase in both urea and creatinine levels.

Where does creatinine primarily originate from?

From the degradation of creatine in the muscles.

What can cause elevated creatinine levels?

Renal disease and dehydration.

What are the two main components of serum proteins?

Albumin and globulins.

What is the primary function of albumin?

To serve as an osmotic regulator and carry bound substances like calcium.

What can cause low total protein levels (hypoproteinaemia)?

Decreased protein synthesis due to starvation, malabsorption, liver disease, and congestive heart failure.

What are common causes of elevated total protein levels (hyperproteinaemia)?

Dehydration and increased globulin levels.

What causes increased albumin levels (hyperalbuminaemia)?

Dehydration, which reduces water content in the blood.

What conditions can lead to decreased albumin levels (hypoalbuminaemia)?

Decreased protein synthesis, increased protein loss, and exocrine pancreatic insufficiency (EPI).

What are common causes of low calcium levels (hypocalcaemia)?

Hypoalbuminaemia, pancreatitis, and EDTA contamination.

What can cause high calcium levels (hypercalcaemia)?

Tumors like lymphoma, renal disease, and bone growth in young animals.

What are the most common electrolytes tested in veterinary practice?

Sodium (Na), Potassium (K), and Chloride (Cl).

What is a common cause of elevated serum cholesterol?

Hypothyroidism, Cushing's syndrome, liver disease, and pancreatitis.

What is the primary source of blood glucose?

Diet and the breakdown of carbohydrates.

Which hormones control blood glucose levels?

Insulin and glucagon.

What conditions can cause elevated glucose levels (hyperglycaemia)?

Diabetes mellitus, pancreatitis, steroid therapy, or stress.

What can lead to low glucose levels (hypoglycaemia)?

Malabsorption, insulinomas, and liver disorders.