The University of California, Davis offers free FIV DNA testing. They require 2ml of whole blood in an EDTA Vacutainer tube along with complete patient information. Samples on ice must be sent by overnight courier to:
2108 Tupper Hall
Vet med: Medicine & Epid.
Davis, CA 95616
The Pricing Schedule for all their services is available for download at:
Feline Immunodeficiency Virus (FIV)
1. When should a cat be tested?
- a. Any cat or kitten being introduced into a new household with other cats should be tested.
b. Maternal antibodies may interfere with the FIV testing in young kittens. The literature is in disagreement as to when FIV screening may be performed: maternal antibody interference can rarely occur at 4 months but has disappeared by 6 months. Preliminary testing of kittens should be done at 8 weeks and final testing at 6 months. If a kitten tests positive they should be retested at 6 months and isolated until then before introducing into multiple cat households or catteries.
c. Testing should also occur in any cat that has been exposed to other cats of unknown FIV status or of positive FIV status (exposed through bites or other wounds).
d. Cats that are ill should also be tested because FIV can lead to many different illnesses.
2. What type of tests are done?
- a. Initial diagnosis is done by looking for antibodies to FIV in blood. Following exposure, the primary immune response results in low levels of antibodies in blood after 2 weeks. Levels may be low at this point, however, so retesting may be done at 6 weeks to be sure of negative results.
b. The first test is the ELISA (enzyme-linked immunosorbent assay), which is quick and easily done at clinics and individuals' offices.
c. If the ELISA test is positive this result is confirmed by performing a Western Blot (also testing for FIV antibodies), because in some cases ELISA may give false positive results.
d. Sometimes immunofluorescent antibody (IFA) tests are used as an alternative to Western Blots.
3. False Positive
- A false positive with an ELISA test does occur due to interference with maternal antibodies, incorrect interpretation of the in-house ELISA tests, operator error, or occasionally other antibodies mimicking the antibodies to FIV. If a cat is ELISA positive and Western blot-positive, the diagnosis is confirmed.
4. False Negative
- Although the ELISA test is highly specific sometimes the antibody titer is too low in the late or early stage of the disease.