Q. Can HIV tests give false negative results?

Answered by
Dr. G.s.s. Sandeep
and medically reviewed by iCliniq medical review team.
This is a premium question & answer published on Aug 12, 2017

Hello doctor,

One and a half years ago, I had unprotected oral sex. Two weeks later I tested positive for HSV-2. I started having sores in my anus. I was prescribed Acyclovir. But, unfortunately, it did not work for me. Four months ago, I had what I believed was ARS with chills, rashes, nausea, and peripheral neuropathy. I then took an HIV fourth generation test which came out negative. However, my symptoms got worse. The sores in my anus did not heal up, and I suddenly developed psoriasis with psoriatic arthritis. I had pain in my joints including fingers, knees, and elbows. My finger nails have also been affected. There was a change in the color of fingernails, and my nails had thickened. More recently, I took a comprehensive STD panel test. It tested for syphilis, chlamydia, gonorrhea, HIV, Hepatitis B and C, and Herpes 1 and 2. The only positive one was HSV 1 and 2. Now, I am so worried. I strongly feel that I am infected with HIV, but the fourth generation tests are not picking up the p24 antigen or antibodies for a reason. My last sexual exposure was seven months ago.

What other tests can I do to rule out an HIV infection? Since psoriatic arthritis is an immune disorder, could it delay the production of antibodies, hence giving a false negative HIV result? Has my body not produced enough antibodies yet for the test to pick up an HIV infection? How long does the p24 antigen stay detectable in the body following exposure to HIV infection? What are the reasons behind a false negative HIV result? I tested past the three month window period. I tested at five months and seven months post-exposure. Could I have an immunodeficiency that has not been diagnosed and is not making antibodies show up? If antibodies have not been produced by now, will not the p24 antigen still be in the body? How long does the p24 antigen stay in the body? Is there ever a time of HIV infection where both the p24 antigen and antibodies will be missing or too low for the fourth generation tests to pick up? I have read articles online that says there are a few people who do not produce antibodies to HIV at all and they will always have a negative antibody test. How true is that? Please help me.



Welcome to

  • You can go for PCR (polymerase chain reaction) analysis of HIV-1 RNA quantitative analysis.
  • Psoriatic arthritis is not an autoimmune disorder like HIV (human immunodeficiency virus) infection. It is T-lymphocytes mediated. So, there will be no interactions with the ELISA (enzyme-linked immunosorbent assay) test.
  • If you are in the window period, there are chances of minimum antibodies production. The window period depends on the individual's immunity.
  • p24 starts appearing after the 16th day. Fourth generation test can detect only free p24 antigen and with time, the free p24 antigens will be reduced. This will cause false negative results. p24 antigen can be detected as long as clinical symptoms do not appear. Then, gp41 antigens start appearing, which stays life long.
  • ELISA tests give false negative results for approximately two to four weeks of infection.
  • Get a viral culture done if possible. This is much more sensitive and specific.

For more information consult a venereologist online -->

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