D80
Blood (Serum) Chemistry

Description: The serum chemistry profile is one of the most important initial tests that is commonly performed on sick animals. A blood sample is collected from the cow. The blood is then separated into a cell layer and serum layer by spinning the sample at high speeds in a machine called a centrifuge. The serum layer is drawn off and a variety of compounds are then measured. These measurements aid the veterinarian in assessing the function of various organs and body systems.

Diagnostic Value: Very high. Sometimes a specific diagnosis may be made on the basis of a blood chemistry profile alone. More often than not, however, the profile provides information on a variety of body organs and systems, giving the doctor an indication of where a problem might be. The profile can be extremely helpful in determining which of the many other diagnostic tests might be beneficial.

Risks to Patient: Virtually none, providing that the blood is collected under sterile conditions by a trained professional.

Relative Cost: Low.

Normal Ranges: The following is a list of the normal ranges in cattle for some of the major parameters on a chemistry profile:

Glucose: 45-95 mg/dl
Blood urea nitrogen (BUN): 7-25 mg/dl
Creatinine: 0.9-1.7 mg/dl
Calcium: 7.6-12.4 mg/dl
Phosphorus: 4.0-8.6 mg/dl
Total protein: 6.4-9.5 g/dl
Albumin: 2.5-4.3 g/dl
Alkaline Phosphatase (ALP): 30-145 IU/L
Sorbitol Dehydrogenase (SDH): 8-55 IU/L
Aspartate Aminotransferase (AST): 40-130 IU/L
Creatine Phosphokinase (CPK): 59-380 IU/L
Chloride: 95-105 mEq/L
Potassium: 4.0-5.8 mEq/L
Sodium: 136-152 mEq/L

Refer to the following information for the interpretation of some of the results found on a blood chemistry.

Interpretation of Results:

  1. Glucose - This is a measurement of the blood sugar level.
  1. High glucose levels can occur during stressful situations, and in association with the use of certain drugs (steroid administration).
  2. Low glucose levels can occur when an animal does not eat, or when there is a severe bacterial infection in the bloodstream.
  1. Blood urea nitrogen (BUN) - Urea, which is normally excreted by the kidney, is a by-product of protein metabolism.
  1. High levels of BUN may be the result of kidney disease, or blockage of the normal flow of urine (from a kidney or bladder stone, for example).
  2. Low BUN levels can result from a low protein diet or liver disease.
  1. Calcium - Calcium, a mineral normally found in the body, is important for normal muscle and heart function.
  1. High calcium levels may be found in some plant intoxications, some types of cancer, excessive dietary supplements, and a variety of other conditions.
  2. Low calcium levels most often occur in a lactating cow (milk fever), or an animal with grass tetany.
  1. Total Protein - Several protein types circulate in the bloodstream. These protein types can be measured all together or may be separated out and measured one at a time. On a routine blood chemistry profile, total protein is measured as the total of all proteins together. Albumin, the most abundant protein type, is usually measured separately.
  1. High protein levels may result from grain overload, peritonitis, salt toxicity, dehydration, inflammation, some cancers, and infections.
  2. Low protein levels can occur in situations of malnutrition, intestine absorption problems, blood loss, and kidney or liver disease.
  1. Creatine Phosphokinase (CPK) - This is an enzyme found in muscle cells.
  1. High CPK levels can occur in situations where muscles of the body are damaged (down cow), diseased, or inflamed. This can even occur with heart muscle problems. Selenium and vitamin E deficiencies are also a cause for elevated CPK levels.
  1. Alkaline Phosphatase (ALP) - This is an enzyme found in liver and bone cells.
  1. High ALP levels may indicate a liver problem, liver flukes, and pyrrolizidine alkaloid toxicity. High levels of ALP can be normal in
    growing calves.
  1. Sorbitol Dehydrogenase (SDH) - This is another liver specific enzyme.
  1. High levels of SDH indicate liver damage and rumen or intestinal
    problems.
  1. Aspartate Aminotransferase (AST) - This is another enzyme produced by a variety of tissues. Concentrations tend to be highest in muscle and liver cells.
  1. High AST levels occur most often when the muscles and/or the liver are damaged. This damage can occur because of toxins, lack of oxygen, inflammation, metabolic disorders, and other diseases.
  1. Chloride - This is a negatively-charged electrolyte (dissolved salt).
  1. High levels of chloride can occur with diarrhea, dehydration, fluid therapy, and acidosis (where the pH of the body is abnormally low).
  1. Potassium - This is an electrolyte with a positive charge.
  1. High levels are associated with acidosis (where the pH of the body is abnormally low), kidney disease, and with some treatments and syndromes.
  2. Low levels are seen with diarrhea, certain phases of kidney disease, and the administration of some drugs.
  1. Sodium - This is also another electrolyte with a positive charge.
  1. High sodium levels may accompany dehydration (due to diarrhea, diuretics, etc.), and salt poisoning.
  2. Low sodium occurs with diarrhea, fluid therapy, and kidney problems.