Sunday, April 5, 2009

In House Diagnostic Tests: Part 1

Most veterinary clinics are able to perform many diagnostic tests in house or in other words, in the clinic....many times while you wait. Because of this, I thought I'd write a couple blogs on the diagnostic tests we offer at the Arthur Veterinary Clinic. Some tests involve sophisticated equipment, while other tests do not.
Snap Tests
Snap tests are a type of test designed by Idexx Corporation. They are quick and easy to perform. They can be performed in house or stall side.....that is.... in a barn or at a farm. Here's a couple of the ones we perform at the AVC. The Snap 3D test tests for heartworm, Lyme and Ehrlichia in dogs. We use this test daily and recommend all dogs be tested annually. This particular test was negative. The blue dot at the top is the control dot. A positive test would show other blue dots below the control.

The other Snap test shown is the Foal CITE test. This test tests the IgG or antibody level in newborn foals. Foals obtain IgG in the first 12-18 hours from their mother's colostrum. This level should be over 800 mg/dl to provide passive immunity against infection in the newborn foal. We recommend this test on all newborn foals and we perform this test on all foals that are born at the clinic. With this test, the control dots are the two blue dots above the single test sample dot. As you can tell, the control dot on the left is a lighter shade of blue than the control dot on the right. The control dot on the left is the 400 mg/dl level and the control dot on the left is the 800 mg/dl level. The test sample dot should be as dark blue or darker than the right hand control dot for the sample to be over 800 mg/dl. Basically, the darker the better. Pale blue or white means the foal's IgG or antibody is low.

Another common Snap test used tests for Feline Leukemia Virus and Feline Immunodeficiency Virus in cats.
Fecal Tests
Most of you are probably familiar with the standard fecal test. You have probably had to "obtain" a stool sample from your pet to bring to your veterinarian. The principle behind a routine fecal test or fecal flotation is pretty simple. A stool sample is mixed with a special solution in a testing container. A microscope slide is placed on top to trap any parasite ova or eggs which, being lighter that the solution, will float to the top. The slide is then examined under the microscope to determine if and identify what type of ova are in the stool sample. Just remember, your pet can have a negative fecal but still be harboring parasites, depending on the shedding or release of the ova. Here's a picture of the fecal solution, container and microscope slide.
This is a picture of a microscope. First year veterinary students must purchase their own microscope to use in veterinary school. For me, this was quite an investment at the time. I paid $700 in 1983 for a brand new microscope. I splurged and bought a binocular microscope instead of a monocular. Thanks goodness for that! Fortunately, microscopes can last a lifetime if properly taken care of.
This is a chart of parasite ova or eggs as seen under a microscope slides.


Another common lab test performed is the urinalysis. Much information can be obtained from a urine sample. A urine sample can be collected from a pet in three ways. A "free catch" sample can be obtained while the pet is actually urinating.....which can be challenging! The drawback to analyzing a voided sample is the urine can be contaminated with bacteria, cells or blood from the reproductive tract which can make analyzing the results difficult. A urine sample can be obtained by catheterizing a pet. However, this can also result in blood and bacteria from the it is uncomfortable for the pet. The third and preferred method of obtaining a urine sample is by cystocentesis. Cystocentesis involves introducing a small needle, preferably ultrasound guided, into the bladder and removing a urine sample with a syringe. This method is actually tolerated very well by the pet and provides the most accurate sample for analysis. A urinalysis consists of three parts. The first part involves dipping a reagent stick in the urine to test for blood, protein, glucose, bilirubin, pH and ketones. The second part involves testing the specific gravity or concentration of urine using a handheld refractometer. The last part involves looking at a centrifuged portion of the urine sample under the microscope. By doing so, we can look for bacteria, red blood cells, white blood cells, abnormal cells and crystals. This picture shows the reagent strip and the handheld refractometer.

This ends the first part of "In House Diagnostic Tests". For the most part, these are common, routine tests performed on a daily basis at the Arthur Veterinary Clinic. In the second part, I will discuss some of the more sophisticated tests.

No comments:

Post a Comment