What is “Viral Testing” for my Cat?

Kathryn Sarpong, DVM DABVP

Your veterinarian may have recommended viral testing for your kitten or cat.   There are many viruses that infect cats, but “viral testing” usually refers to a blood test that looks for feline leukemia virus (FeLV), and Feline Immunodeficiency Virus (FIV).    These viruses can be deadly and are contagious from contact with other cats.  Sometimes kittens are infected from their mothers.

It is important to test a new cat before introducing it to your other cats. Cats and kittens carrying the viruses may look perfectly healthy. Typically, the blood test can be done in your veterinarian’s office with results available in a few minutes.  The viral testing can also be added onto other blood tests that your veterinarian is doing on your cat for wellness, or when your cat is sick.


Feline Leukemia Virus is spread most commonly from cat to cat by sharing food/ water bowls, grooming, sharing a litter box or close contact.   It results in a lower immune system, anemia and can lead to cancer.  There is a vaccine for this virus that should be given to all kittens and then to adult cats that go outside or get exposed to other cats through fostering, adoption events or open play boarding.

Feline Immunodeficiency Virus (FIV) is a retrovirus similar to HIV in people, that is spread through bite wounds, sexual contact or blood transfusions.   FIV can stay quiet for years or progress to its end state where the cat has a severely compromised immune system.


Cats that go outdoors should be tested at least annually.   Cats should be tested 6 weeks after any fights with another cat of unknown viral status.  All kittens should be tested at least once.  Any new cats should be tested prior to being introduced to other cats in the household. Most stray cat sterilization programs include testing cats for these viruses to reduce the spread.   Confirmation testing can be done for cats that are positive on the in-house tests.   Kittens that test positive may have to wait to perform confirmation testing while any maternal interference clears from their bodies.


Treatments for these viruses are primarily supportive.   These cats should be watched closely for dental disease, eye lesions, anemia, other infections and cancers. The cats should be checked for any organ dysfunction at least annually if not more frequently with a full blood panel test.  The cats need to be maintained indoors and with controlled social interactions where the risks are well understood. FIV positive cats can live in stable happy households.  Feline leukemia virus infected cats are more difficult to manage since it is spread by more casual contact.   Unfortunately, neither of the viruses can be cured from cats once they are infected.  Testing and prevention is the best strategy!