Feline Leukemia Test -
Diagnosing Cat Leukemia

The feline leukemia test is the same regardless of whether the cat is showing feline leukemia symptoms or not.

Cat leukemia testing is normally done if:

  • The cat is showing possible signs of feline leukemia virus (FeLV) infection
  • The cat has been exposed to another cat that's known to have leukemia
  • A cat - for example a stray or one from a shelter - is about to be adopted by someone who already has cats
  • The cat is about to have its first feline leukemia vaccine (the vaccine should not be given to FeLV-positive cats)

Testing for Leukemia in Cats


Photo courtesy of Mike Bartlam

Testing is normally done in 2 stages, both of which require a blood sample. The sample is normally taken from a vein in the cat's front leg, and is relatively easy to obtain; the cat doesn't usually need to be sedated to get it.

Stage 1 - quick test at the veterinary surgery

Vets normally have a testing kit for FeLV which gives a quick, same day result. Without getting too technical, it involves mixing the cat's blood with proteins that specifically bind to the virus. A substance is then added which gives a color change if the proteins have bound to the virus - i.e. if the test is positive.

These quick tests aren't 100% accurate and sometimes give false positives. For this reason, if this test is positive, a second, more accurate test is usually performed.

Stage 2 - diagnostic laboratory test

This test works on a similar principle to the quick test above, but is more specific and accurate.

Many cats that test positive for feline leukemia virus will successfully get rid of the infection. Any cat that tests positive should therefore have a repeat test about 12 weeks later.

Click on this link for more information on feline leukemia treatment.

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