Bloodwork Basics: A Reference Guide
01/01/2004

Your vet can check the complete blood count (CBC), analyze blood chemistry to assess organ function, and check titers to see if disease-fighting antigens are present—all from one sample of your IW’s blood.   Many factors, such as drug interaction and fasting, can affect  results; interpretation takes expertise.

Complete Blood Count (CBC)

The CBC evaluates three types of cells in the blood: red, white, and platelets. Blood cells are manufactured in the bone marrow, and each cell type performs a specific function which is critical to the overall health of the animal.

HEMATOCRIT gives the proportion of the blood, by volume, which consists of red blood cells. A low hematocrit (anemia) may have many causes. High hematocrits are seen in many sighthounds, and in animals living at high altitudes, and also in dehydration.

HEMOGLOBIN is the iron-rich protein in red blood cells. Since oxygen travels through the bloodstream bound to hemoglobin, this measurement indicates how much oxygen the blood can carry throughout the body.

WBC are the white blood cells, or leukocytes which fight infection in the body, and transport antibodies to sites of infection. An abnormal white cell count can indicate infection, inflammation, or other stress.  Normal WBC values for Irish Wolfhounds are frequently at the very low end of normal range.

RBC or Red Blood Cell Count. In addition to carrying oxygen to the tissues, red blood cells also transfer carbon dioxide to the lungs.

MCV or Mean Corpuscular Volume. This value gives the size of the red blood cells, by measuring the volume of a single red cell.

MCH or Mean Corpuscular Hemoglobin. This measures the average weight of hemoglobin in the red blood cell.

MCHC is the mean corpuscular hemoglobin concentration. This test uses hemoglobin and hematocrit for calculation, rather than the red blood cell. MCV, MCH, and MCHC are most useful in assessing anemia, and in choosing therapy to treat it.

PLATELETS are also known as thrombocytes, and are vital to coagulation. Decreased levels may mean an immune system failure, or deficiency of B12 or folic acid. Increased levels are seen in dehydration.

The DIFFERENTIAL count measures the numbers of the different types of white cells in the bloodstream. Each of these five cell types has a specific role to play.

NEUTROPHILS are the body’s soldiers, defending against invaders. They are the body’s chief defense against antigens and infection.  Bands are immature neutrophils.

EOSINOPHILS and BASOPHILS in the blood may be increased in allergic conditions, or in infestations with ecto/endo parasites. (EOS and BASOS).

LYMPHOCYTES produce antibodies, but most circulating in the bloodstream either attack invaders or coordinate the attack of antibodies. They are especially important in fighting viral infections.

MONOCYTES are the body’s second line of defense against infection. Elevated levels are seen in tissue breakdown, chronic infection, and certain types of cancer.

Blood Chemistry

GLUCOSE is the main source of energy. It is regulated by insulin produced in the pancreas, and other hormones and enzymes.

Kidney Function

CREATININE and B.U.N. are normally removed by the kidneys and excreted in urine. Elevated levels may reflect heart or kidney disease, among other things. Urea Nitrogen (B.U.N.) is the end waste
product of protein metabolism. Creatinine is a waste product of muscle metabolism.

Protein

TOTAL PROTEIN  Proteins are the most numerous compounds in serum. Elevated levels can indicate, among other things, liver disease, lupus, or chronic infection.

ALBUMIN accounts for over 50% of serum protein, and it is manufactured by the liver.

GLOBULIN is important in immunologic responses, especially its gamma component. Higher levels in the bloodstream can be from chronic infection, whereas low levels results from immune compromise or liver or kidney disease.

Liver Function

ALT (Alanine aminotransferase), was formerly called SGPT. It is an enzyme found primarily in the liver, and its level is useful in diagnosing liver damage.

AST (Aspartate aminotransferase) is found primarily in the liver. Increased levels are found when there is severe diffuse hepatic insult, and also when there is tissue damage, kidney infection, or other problems. When levels are decreased, along with increased cholesterol levels, it is seen in cases of congested liver disease.

ALKALINE PHOSPHATASE This enzyme is produced in the cells of the bone and liver, and elevated levels can be a marker for tumors.

BILIRUBIN is a by-product of the breakdown of hemoglobin. It is a good indication of the liver’s function.

GGTP (Gamma-Glutamyltransferase, or Gamma-Glutamyl Transpeptidase). Elevated levels are found in liver disease and bile-duct obstruction.

CHOLESTEROL is a critical fat that is involved in many important cell functions. Dogs, unlike humans, do not really suffer from the artherosclerosis associated with consuming high-fat foods.

Pancreas

LIPASE is a pancreas-specific enzyme, and, when elevated levels are found in the blood, it is an indication that damage to the pancreas has occurred.

AMYLASE is manufactured in the pancreas and in the digestive tract, and, along with lipase, can indicate damage to the pancreas. However, the pancreas can be very inflamed without a rise in either value.

Electrolytes

CALCIUM All cells require calcium to function. It is crucial in bone structure and neuromuscular activity. Calcium deficiency in the body fluids causes hyperexcitable nerves and muscles.

POTASSIUM is the major positive ion within cells. Abnormally high values are associated with hemolysis (destruction of red blood cells), Addison’s disease, diarrhea, and renal failure. Low levels can be seen in Cushing’s disease, or after vomiting.

PHOSPHORUS levels are inversely related to calcium levels.

SODIUM, POTASSIUM, and CHLORIDE  These three minerals are particularly important for nerve and muscle function and water balance. They help maintain osmotic pressure, and are involved in maintaining the acid-base balance.

CO2 (Carbon dioxide) CO2 levels are related to the respiratory exchange rate as well as kidney function. When looked at along with the other electrolytes, it is generally a good indicator of acidity and alkalinity.

A/G (Anion Gap) This ratio measures the concentration of cations (sodium, potassium) and the anions (chloride, CO2) in the extracellular fluid. An increase in this measurement can reflect metabolic acidosis or alkalosis.

CPK measures creatine phosphokinase (CPK), an enzyme found predominantly in the heart, brain, and skeletal muscle. When the total CPK level is substantially elevated, it usually indicates injury or stress to one or moreof these areas.

TITER A titer measures antibodies to a specific substance, thus providing information  about your dog’s immunity to a particular disease.

OSMOLALITY Values reflect the hydration at time of testing. Osmolality increases with dehydration, and decreases with overhydration.