How to Tell If a Cat Really Has FIV

A major problem with the FIV vaccine is that one particular side effect could be more dangerous than the disease itself.

The standard FIV test can't tell the difference between cats who have been vaccinated against FIV and cats who really have FIV, so vaccinated cats could be killed in shelters.

Renowned cat researcher Julie Levy at the University of Florida has figured out a practical solution to the problem. Cats who test positive on a normal screening test should be re-tested using a more sensitive ELISA test. If the ELISA test is positive, the cat has FIV; if negative, the cat is a healthy vaccinee.

Levy JK, Crawford PC, Kusuhara H, Motokawa K, Gemma T, Watanabe R, Arai S, Bienzle D, Hohdatsu T. Differentiation of feline immunodeficiency virus vaccination, infection, or vaccination and infection in cats. Journal of Veterinary Internal Medicine 2008 Mar–Apr;22(2):330–334.