My kitten tested positive for feline leukemia. Can it be a false positive?

Hi and thanks for using PetCoach! Sorry to hear about Boots. I have never personally heard that for Feline Leukemia. The vaccines for FeLV do not cause a positive test result BUT previous FIV (Feline Immunodeficiency Virus) vaccines cause a positive test result that cannot be differentiated from a natural infection. One positive FeLV test in a healthy cat is always suspect. False positives do occur and if you really want to know, I would advise that you go get a confirmation test done at your veterinarians office. The test is called an IFA or Immuno Fluorescent Antibody test and this is specific for FeLV. This disease along with FIV are very complex and sometimes very confusing with respect to the results. Let me provide a website link here so you can learn more about these retroviruses in cats. Good luck with Boots. https://www.catvets.com/guidelines/practice-guidelines/retrovirus-management-guidelines

Most tests are fairly accurate if the results are negative. However there can be false positive test results if done early in age due to antibodies from the mother. I would recommend a vet visit and discuss your concerns with Cagney's vet. But many times it is worth testing earlier and start vaccines. If the test is positive then further testing or quarentine may be required but if negative he may be able to be intetgrated into the rest of the household.

a blood smear is quite reliable but i would still recommend having an additional blood test (Elisa, IFA or PCR) to have a confirmation. unfortunately the disease is not curable but it is manageable and many cats can live many years with the disease.

FeLV is a non-curable disease which means that once your cat has it he will carry the virus for the duration of his life. I am not sure which SNAP test was used on Tom, but the IDEXX FeLV/FIV SNAP has a sensitivity of 98.6% and a Specificity of 98.2% for FeLV. This means that there is only a 1.8% chance of a false positive on the SNAP. However, it is important to note that cats who have been vaccinated for FeLV can show a positive result on the SNAP. IDEXX recommends that any positive FeLV SNAP be confirmed by IFA. Although there are no statistics shown for discrepant results, they do recommend repeat testing after 28 days rather than euthanasia: http://www.idexx.com.tw/pdf/zh_tw/smallanimal/snap/triple/fiv-felv-diagnostic-guidelines.pdf

You have a little bit of a tricky situation. The only way your 8 year old cat can get Feline Leukemia is if the kitten is infected and shedding the virus. Since the kitten tested negative before you brought him home, you know he was not shedding the virus at that time. BUT since you know he was around another cat that could have have been shedding the virus, he could still become positive from that exposure (which can take a little while to test positive for). The safest thing to do for your 8 year old cat would be to keep him separated from the kitten for the next 90 days, then retest the kitten for Feline Leukemia. If he is negative at that time, then you can reintroduce them. Good luck! I hope everything is fine and that was helpful. Let us know if that doesn't make sense or if you have any other questions. Thanks for using Petco Pet Education Center, formerly Petcoach.

Panleukopenia is a feline parvovirus. They don't make a direct test for it but most clinics use the canine parvovirus test to get a result. False positives are very rare, occurring only in about 0-6% of tested samples. Vaccine induced positives are also rare with about only 1/64 recently vaccinated kittens testing positive. This is with the IDEXX brand test. Other brands had a higher rate of positive results following vaccination. So, without more information as to what test your vet used and how long ago she was vaccinated and with what vaccine (if she was even vaccinated) it is difficult for me to say much on the subject. If an IDEXX test was used I would trust the result. Hope this helps. Best wishes.

Oh dear, I'm sorry to hear that Stassi has been diagnosed with lymphoma. If Stassi and all of your other cats have been indoors only, and were all negative for FeLV to start with, there is next to no chance that your other cats have contracted or will contract FeLV. It is statistically improbable that Stassi has tested negative for FeLV four times and would still have FeLV, unless she may have been exposed to another cat in the past 4-5 years that has FeLV. Lymphoma is a fairly common type of cancer that can occur in cats with or without FeLV. I hope that helps to clarify your concerns. I'm really sorry that you and Stassi are going through this situation.