Testing for Feline Leukemia Virus (FeLV) and Feline Immunodeficiency Virus (FIV)

Testing your cat for FeLV/FIV is a personal decision. We do not suggest that you don't test, but, speak to your vet about options if the cat tests positive.  TeamTNR doesn't routinely test as we follow the advice of Alley Cat Allies ( , the premier TNR group in the US, whose policies are based on current scientific research. 


Protocols: Testing - Feline Immunodeficiency Virus (FIV) and Feline Leukemia Virus (FeLV)
FIV and FeLV are incurable viruses that only affect cats. Humans cannot catch or transmit these viruses. Not all cats that become infected will develop disease.

Cats who test positive for FIV often live long, healthy lives. Many veterinary spay and neuter clinics do not test feral cats for FeLV or FIV, because most feral cats enjoy excellent health and are no more likely to be infected with disease than owned cats. In fact, owned cats and feral cats contract FeLV and FIV at an equally low rate (about 4%).*

Alley Cat Allies does not support testing feral cats for FIV and FeLV for multiple reasons:

  • The percentage of feral cats infected with either FeLV or FIV is low. Studies detected FeLV in 4.3% of cats; FIV in 3.5%. This is similar to the rate in owned cats. Several large-scale spay/neuter clinics in the U.S. report only a 1-2% incidence of FeLV in the early years when every cat is tested. 
  • Test results can be unreliable and can result in false positives. Cats testing positive should be re-tested at least 28 days after the cat's last possible exposure to the virus.
  • Spaying or neutering cats inhibits the spread of the viruses. Since spaying and neutering reduces or eliminates the primary modes of transmission, such as fighting and breeding, infected cats pose less risk to other cats. 
  • Infected cats are often asymptomatic and can remain healthy with no sign of illness for many years or for their entire life; considering all factors, more cats likely die from having positive test results than die from FIV-related disease. 
  • And testing can be prohibitively expensive. The cost of testing (and often re-testing because of false positive test results) hinders the success of a spay/neuter program. The goal of the program is to spay or neuter as many cats as possible. Resources are best applied to spaying and neutering more cats. And, increasing the number of cats that are spayed or neutered decreases the incidence of virus transmission
  • FIV tests do not differentiate between FIV infection and FIV vaccination. A positive test is likely to result in euthanizing vaccinated cats that are not infected.

Learn more about FIV ( and FeLV (

Alley Cat Allies does not support the euthanasia of healthy cats who test positive for FeLV and FIV. The American Association of Feline Practitioners ( agrees, recommending against routine euthanasia of healthy FeLV- and FIV-positive cats.

Euthanasia n. The act or practice of ending the life of an individual suffering from a terminal illness or incurable condition, as by lethal injection of the suspension of extraordinary medical treatment. The American Heritage Dictionary.

Learn more about the difference between euthanasia and killing at

All cats showing signs of illness or injury should be trapped and taken to a vet for medical treatment.

*"Prevalence of feline leukemia virus infection and serium antibodies against feline immunodeficiency virus in unowned free-roaming cats", JAVMA, Vol 220, No.5, March 1, 2002

  © 2012 Alley Cat Allies