In order to diagnose feline leukemia, the vet may ask the cat’s owner some questions like whether it is an indoors only cat or one that mingles with other stray cats. Then, a physical exam will be conducted to understand the cats overall health. A number of diagnostic tests help identify and confirm feline leukemia.

The main test used to diagnose feline leukemia is the ELISA (Enzyme Linked Immunosorbent Assay). This test analyzes samples of blood, saliva or tears to check for the presence of the virus. Most cats will test positive within 28 days of exposure. The test makes use of a simple ELISA kit and results can be obtained within 10 to 15 minutes. If a cat tests positive for feline leukemia virus, another ELISA test may be recommended after 30 days because in some cases, the body is able to fight the infection and the second test may emerge negative or the first test may show a false positive or negative.

An additional Immunofluorescent Antibody (IFA) test may also be conducted to confirm the results of ELISA. This test checks for the presence of viral infection in the white blood cells. Some labs offer PCR (Polymerase Chain Reaction) tests for identifying feline leukemia.