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

Feline leukemia virus (FeLV) and feline immunodeficiency virus (FIV) testing


  • FIV and FeLV are deadly viral diseases that infect cats
  • Test new cats before introducing them to your existing cats
  • Separate positive cats from negative cats to prevent transmission
  • Keep cats indoors to prevent fighting with neighborhood cats
  • Vaccinate outdoor cats for FeLV
  • Provide additional care for infected cats

Feline leukemia virus (FeLV) and feline immunodeficiency virus (FIV) are common viral diseases that infect cats. They are in the retrovirus family, and cause illness and death.

Infection is via a bite or a scratch, or the viruses can spread from mother to kitten across the placenta. FeLV can also spread by close contact, grooming, and shared litterboxes over a period of time. The viruses do not survive outside the body for more than a few hours. Infected cats can appear healthy or they may look sick.

FIV causes chronic diarrhea, bad breath, dental disease, a poor coat, weight loss, skin infections, and other clinical signs related to a suppressed immune system.

FeLV causes cancer including lymphoma and leukemia, anemia, chronic infections, weight loss, and other problems.

Current recommendations at Evesham Veterinary Clinic are that new kittens and adult cats being brought into a home for the first time be tested for FIV and FeLV. We also frequently recommend testing on sick cats, especially those that spend any time outdoors.

We use the Idexx SNAP FIV/FeLV Combo Test, based on ELISA technology. The test is safe, quick, reliable, and affordable. It requires a few drops of blood and takes ten minutes in the office to run.

The Idexx SNAP test is very sensitive, meaning it will give very few false negatives. Recent infection is one cause of false negatives.

The test is also very specific, but there are instances where false positives may occur:

  • Positive mother, young negative kitten carrying maternal antibodies to FIV
  • FeLV infected cat that spontaneously clears the infection on his own (very rare)

The test may be confirmed by Western Blot for FIV or an IFA test for FeLV. Young kittens who test positive for FIV can be retested by the SNAP test when they are older.

Positive tests alone are not an indication for euthanasia in an otherwise healthy cat. In some cases, the FeLV and FIV viruses can lie dormant for years and these cats can enjoy an excellent quality of life.

In recent years, a misperception about the test has spread among a large number of people. Many individuals who work with kittens are recommending to delay testing until they are six months old because of the chance of false positives due to maternal antibodies. The rationale is that a positive test could result in euthanasia of a healthy animal.

We disagree with this approach for several reasons. Not knowing the FIV and FeLV status puts other cats at risk of infection, and it misses the opportunity to provide increased care for the infected kitten. Although there are some infected kittens that do very well, the majority become ill and have significantly shortened lifespans. Families deserve the opportunity to decide for themselves if they are willing to take on the emotional costs of adopting a positive kitten.

The test has limitations, but one thing it is very good at is detecting positives. If your new kitten tests negative, you have peace of mind knowing there is very little chance your kitten is infected.

The viruses pose no direct threat to humans. However, positive cats can have a difficult time clearing other infectious diseases, and they may shed them into their environment. For this reason we recommend against bringing these cats into a household where any humans are themselves immunocompromised.

A vaccine is available for FeLV.  It is very good, and currently recommended for all cats who spend time outdoors or who live with a positive cat.

There is also a vaccine available for FIV,  but it is reserved for cats at high risk of contracting the disease.  It will make cats test positive on the SNAP test, so all vaccinated cats must be microchipped.

If you have any questions or would like to have your cat tested for FIV and FeLV, please call us at (856) 983-9440.




(856) 983-9440