FeLV & FIV Testing: What Every Cat Owner Should Know

FeLV and FIV are often screened together on the same small blood sample, but the tests work differently. FeLV screening usually detects p27 antigen, which means viral protein is present in the bloodstream. FIV screening usually detects antibodies, which means the immune system has responded to infection.

That difference matters in real life. A cat with FeLV may test positive during active antigenemia, while a cat with FIV may test positive because of infection, maternal antibodies in a young kitten, or past FIV vaccination history. Because of that, your vet may recommend confirmatory testing instead of making major decisions from one screening result alone.

Testing is commonly recommended for all newly adopted cats, all kittens, cats with unknown history, cats entering a home with other cats, and cats that are sick, even if they tested negative before. Cats with outdoor access, bite wounds, or contact with infected or unknown-status cats may need repeat testing.

Recent exposure can create a testing window. For FIV, antibodies may take up to about 8 weeks to develop, so a recently infected cat can test negative early on. For FeLV, infection status can also be unclear from one test, especially in healthy cats, so your vet may recommend repeat or confirmatory testing after an exposure or an unexpected positive result.

No screening test is perfect. FIV false positives can happen in kittens carrying maternal antibodies and in cats with a history of FIV vaccination. FeLV positives can also need confirmation because some cats have transient antigenemia or infection patterns that are harder to classify from one sample.

False negatives are also possible. A cat tested too soon after exposure may not yet have detectable markers. That is why timing, symptoms, age, and vaccination history all matter. If the result does not fit the cat in front of your vet, the next step is usually more testing, not panic.

A positive screening result usually leads to a conversation about confirmation, household risk, and next steps. For FeLV, confirmatory options may include PCR, referral laboratory antigen testing, or another validated test method. For FIV, your vet may recommend retesting later in kittens or using PCR or another confirmatory approach when the result is uncertain.

If infection is confirmed, many cats can still have meaningful, comfortable lives with regular monitoring and lower-stress routines. Management often focuses on wellness exams, dental care, parasite prevention, prompt attention to illness, and reducing exposure to other cats. FeLV-positive cats may have a more guarded long-term outlook overall, but some live well for years. FIV-positive cats can also do well for long periods, especially with good preventive care.

In the United States in 2025-2026, a combined in-clinic FeLV/FIV screening test commonly falls around $75-$150 for the test itself. A wellness or sick visit exam fee is often separate and may add roughly $25-$186, depending on region and clinic type.

If a result needs confirmation, costs can rise. Additional PCR or referral laboratory confirmation may add about $80-$220+ depending on the lab and whether shipping, consultation, or repeat exam fees are involved. Ask your vet for an estimate that separates the screening test, exam, and any follow-up testing so you can plan clearly.

If your cat has never been tested, or if the last test was before a possible exposure, bring it up at the next visit. This is especially important for kittens, newly adopted cats, outdoor cats, and cats joining a multi-cat household. If your cat is sick, testing may be part of the workup even if they seem low-risk.

Try not to interpret a result in isolation. The most useful questions are: What does this test detect? Could this be too early? Does my cat need confirmation? How does this affect other cats in the home? Your vet can help you build a plan that fits both your cat's medical needs and your household realities.