Introduction
Infection by the feline immunodeficiency virus (FIV) can be diagnosed by a number of blood tests which can identify antibodies in the cat’s blood caused by previous exposure to the virus. Most of these tests can be performed at a veterinarian clinic; others will be submitted to an outside laboratory.
Diagnosing Feline Immunodeficiency Virus
The treating veterinarian will select the appropriate test(s) in any given case. Currently, the screening test of choice is the enzyme-linked immunosorbent assay (ELISA), which can detect anti-FIV antibodies in a cat’s saliva or serum if it has been exposed to and infected by the virus. The ELISA test can have false-positive results when the cat has been vaccinated against FIV, in kittens who still have colostrum-derived maternal antibodies against FIV and occasionally due to laboratory error. Positive results from the ELISA screening test should be confirmed by either a Western Blot or polymerase chain reaction (PCR) test.
It can take several months for detectable levels of FIV antibodies to form in the blood after the initial infection occurs. Kittens and cats with unknown vaccination histories should be tested at least twice for the disease. Cats that are in a high-risk group for FIV infections, such as outdoor non-neutered males or cats prone to fight with other cats, should be tested for FIV at least annually.