Blood test results

The results of the tests are in and you're confused, and understandably so.

There are a lot of tests that can be run on your pet depending on what the veterinarian is looking for, but I’m only going to address the basic values tested on what is commonly referred to as a “general health panel” (GHP). The enzyme assays that are done are snapshots of the liver, kidneys and pancreas.

The IDEXX in-house test pack consists of the following:

Albumin

Alkaline Phosphatase (alk phos)

Alanine Aminotransferase (ALT)

Amylase

Blood Urea Nitrogen (BUN)

Calcium

Cholesterol

Creatinine

Glucose

Phosphorus

Total Bilirubin

Total Protein

Lipase is often added onto the test if there is a possibility of pancreatitis.

The basic Antech diagnostic test known as the VetScreen contains the above plus: Chloride, CPK, Globulin, Potassium and Sodium. However, whenever we run an Idexx GHP we also use the VetLyte machine to obtain the electrolytes sodium, potassium and chloride.

Let’s address the IDEXX GHP.

Albumin is a protein plasma or serum and makes up 35-50% of the total plasma protein; its primary function is to maintain the osmotic pressure of the plasma, which prevents fluid saturation of tissues. Liver cells are responsible for the synthesis of albumin and if it is compromised there will be a decrease in albumin. However, renal disease and diet can also have an effect on the level of albumin.

Alkaline Phosphatase (alk phos) is produced by the liver and bone tissues. In young animals it mostly comes from the bone due to bone development. In older pets it is produced predominantly by the liver. When a vet is suspecting cholestasis (blockage of bile excretion) they are looking for a concentration of alkaline phosphatase. Alk phos can also be increased due to a metabolic defect in liver cells.

Alanine Aminotransferase (ALT) is considered liver-specific in dogs and cats. It is used as a screening test for liver disease but will not diagnose the disease itself. You may also see an increase in ALT when there is damage to renal cells, skeletal muscles, the pancreas and the muscles of the heart. Hemolysis and lipemia can also cause a false high reading.

Amylase is primarily produced by the pancreas and its job is to break down starches and glycogen present in sugar. Pancreatitis and obstruction of the pancreatic ducts can cause an increased level of amylase. The increase of amylase in itself is not indicative of the severity of pancreatitis but is used in conjunction with lipase to do so. Hemolysis and lipemia can give false results.

Blood Urea Nitrogen (BUN) levels are evaluated to determine the kidney’s ability to remove urea from the blood. The problem with this test is that an increased BUN value will not be detected until there is about 75% of kidney malfunction. Increased BUN alone is not indicative of kidney disease.

Calcium is mostly found in the bones of the body. <1% has major functions in the body. It is responsible for the facilitation of blood coagulation and a decrease in calcium can cause muscle tetany. Low calcium levels are also seen with hypoparathyroidism. When there is an increase in calcium levels the phosphorus levels are seen to drop.

Cholesterol is produced in almost every cell of the body. When a pet has just eaten recently, this level, along with triglycerides, may be increased. An increase in cholesterol may be seen with diabetes mellitus, hyperadrenocortism, and hypothyroidism. Rarely does diet cause an increase in cholesterol.

Creatinine is formed by the break down of creatine and then diffused into the blood and most other body fluids. It is then filtered through the kidneys and eliminated in the urine. The glomeruli of the kidneys filters the Creatinine out of the blood. If there is at least 75% of kidney damage then you will see a rise in Creatinine levels. Creatinine is not affected by a high-protein diet.

Glucose measures the function of the pancreas, indicates carbohydrate metabolism, reflects glucose production and utilization as well as the balance between blood insulin and glucagons levels. An increase in glucose can be indicative of diabetes mellitus. Felines have a tendency to have a mild increase in glucose due to stress during the veterinary visit and blood draw.

Phosphorus, like Calcium, is mostly found in the bones. <20% has the function of energy storage and is involved in carbohydrate metabolism. Most phosphorus found in whole blood is from the red blood cells themselves. Hemolysis can cause an increase in phosphorus.

Bilirubin is a waste product of red blood cells. There is conjugated and unconjugated bilirubin. Unconjugated+conjugated bilirubin=total bilirubin which is evaluated to help determine liver function and if bile ducts are doing their job. Increased conjugated bilirubin is seen with liver cell damage or bile duct obstruction. Increases in unconjugated bilirubin are seen with excessive red blood cell damage.

Total Protein measures hydration. Dehydration is indicated with an increase in total protein and over-hydration a decrease.

Lipase is produced by the pancreas. Its primary purpose is to break down lipids. A gross increase in lipase is seen with pancreatitis.