LABORATORY TESTING

During your pet’s routine wellness exam or if it is suspected that something is wrong, your veterinarian may wish to run laboratory tests using a sample of your pet’s blood, urine, skin, hair or feces. These tests are important to help your veterinarian understand your pet’s health status.

When your pet is healthy, your veterinarian may run laboratory tests, such as a complete blood count (CBC), chemistry panel and urinalysis, to establish your pet’s “baseline” values. Then, if your pet ever gets sick, your veterinarian will compare your pet’s current laboratory results to his previous baseline value to determine if the current values are abnormal.

When your pet is sick, laboratory test results will help your veterinarian confirm the presence of certain illnesses and rule out other diseases. Your veterinarian may also run laboratory tests during treatment to track the path of the disease and see how your pet responds to treatment.

If your pet is scheduled for surgery, your veterinarian may run pre-surgical screening tests in order to determine if your pet is at risk of complications while under general anesthesia. These screening tests may be recommended for pets of all ages, including young, healthy pets.

How quickly will I learn the results of my pet’s lab tests?
If your veterinarian has laboratory testing equipment at his practice, your pet’s results may be available that same day or even within a few minutes. Many veterinary hospitals have the equipment necessary to perform some tests in-house, but send other tests to a large, commercial laboratory, in which case the results are most often available within 24 hours.

What kinds of laboratory tests are available?
Your veterinarian will take into account your pet’s symptoms, breed, age and sex when recommending laboratory tests. The following are the most common laboratory tests in veterinary practice.

Complete Blood Count (CBC)
A CBC measures the number of red blood cells, white blood cells and platelets in a sample of blood. The numbers of each type of cell give your veterinarian information to help him diagnose anemia, infections and leukemia. If your pet is undergoing treatment for a condition, a complete blood count can help your veterinarian monitor how your pet is responding to the treatment.

Urinalysis (UA)
Laboratory testing of your pet’s urine will help your veterinarian detect the presence of specific substances that normally do not appear in urine, including protein, sugar, white blood cells or blood. Measuring the dilution or concentration of urine can also help your veterinarian diagnose illness. Urinalysis can be helpful in diagnosing urinary-tract infections, diabetes, dehydration, kidney problems and other conditions.

Blood-Chemistry Panel
A blood-chemistry panel measures your pet’s electrolytes, enzymes and chemical elements of his blood such as calcium and phosphorous levels. These measurements help your veterinarian determine how your pet’s organs, such as kidneys, pancreas and liver, are currently functioning. Blood-chemistry panels also help your veterinarian accurately diagnose and treat illness, as well as monitor your pet’s response to treatment. Your veterinarian may also use the results of a blood-chemistry panel to determine if further testing is needed.

Your veterinarian may recommend a chemistry panel to obtain your pet’s baseline values, which can be compared to later tests. Any differences between the baseline values and values measured at a later time will help your veterinarian diagnose new problems.

Heartworm Test
Your veterinarian may recommend a blood test to confirm the presence of heartworms in your pet. Several different heartworm tests will show the presence of microfilariae (offspring of adult heartworms) in your pet’s blood. There are other blood tests that confirm the presence of adult heartworms by detecting certain substances in the bloodstream. For more information about heartworm, see the Healthypet article Heartworm Disease.

Fecal Examination
Your veterinarian may examine your pet’s feces under a microscope for clues about many different kinds of diseases, including difficulties with digestion, internal bleeding and pancreas disorders. Most importantly, fecal examination will confirm the presence of intestinal parasites, including roundworm, hookworm, whipworm, tapeworm and giardia. For more information about parasites, see the PurrfectPaws article External and Internal Parasites.

Skin Scraping
Skin scraping is one of the most common tests in veterinary dermatology. Your veterinarian will take a small scraping of your pet’s skin and examine it under a microscope to confirm the presence of certain types of fungi or microscopic parasites on your pet’s skin.

Fungal Culture
Your veterinarian may take a few hair samples if he is concerned about the possibility of a fungal infection on your pet’s skin. A culture test can be performed on the hair sample to detect the presence of fungi such as ringworm. Unlike other laboratory tests, it usually takes one to two weeks to get a final result from a fungal culture.

Test of Thyroid Function
A thyroid gland that is not functioning properly may not be producing hormones that are vital to maintaining normal growth and metabolism, or it may be producing too much hormone. Your veterinarian will measure the hormone concentrations in the thyroid gland to determine if your pet’s thyroid is functioning properly.

Fine-Needle Aspirates
If your pet has an unusual lump or bump on his skin, your veterinarian may take a sample of it using a hollow needle to withdraw cells and/or fluid from the lump. Your veterinarian will examine the sample on a slide under a microscope to help diagnose infections or cancer. Fine-needle aspirates also provide information about whether a tumor is malignant or benign, and if additional testing or treatment is needed.

Test for Feline Immunodeficiency Diseases
Your veterinarian may recommend a test to determine whether or not your cat has contracted feline immunodeficiency virus or feline leukemia virus. Your veterinarian will take a blood sample to perform an enzyme-linked immunosorbent assay (ELISA) to diagnose these viruses.

Laboratory testing can help catch many conditions early before they become serious illnesses, so be sure to ask your veterinarian about which tests your pet may need during your pet’s next wellness exam.