What Happens If You Get a False Positive for HIV?

Medically reviewed by Timothy J. Legg, PhD, CRNP, ACRN on April 29, 2016Written by Traci Angel on April 29, 2016


UPDATE COMING We’re currently working to update this article. that a person living with HIV who is on regular antiretroviral therapy that reduces the virus to undetectable levels in the blood is NOT able to transmit HIV to a partner during sex. This page will be updated soon to reflect the medical consensus that “Undetectable = Untransmittable.”

HIV is a virus that attacks the immune system. The virus specifically attacks your T cells, which are responsible for fighting infection. When this virus attacks these cells, it reduces the overall number of T cells in your body. This weakens your immune system and can make you more susceptive to illness.

If you don’t get treatment for it, HIV can lead to AIDS. This occurs when the virus has destroyed so many T cells that your body is no longer able to fight off infection or disease. AIDS is the last stage of HIV infection. Not everyone with HIV will develop AIDS.

Unlike other viruses, your immune system can’t get rid of this virus completely. This means that once you have the virus, you have it for life.

How is HIV transmitted?

People typically spread HIV through sexual intercourse. This is because the virus is spread through certain bodily fluids, including:

  • pre-seminal fluids
  • semen
  • vaginal fluids
  • rectal fluids

This means you can spread the virus through oral, vaginal, or anal intercourse.

You can also spread HIV through blood. This commonly occurs among people who share needles or other drug injection equipment.

Mothers can infect their babies during pregnancy or delivery through vaginal fluids. Mothers who have HIV can also pass the virus on to babies through their breast milk.

Learn more: Early signs of HIV »

How is HIV diagnosed?

Doctors typically use an enzyme-linked immunosorbent assay, or ELISA test, to test for HIV. This test detects and measures the antibodies in your blood. If you give a blood sample using a finger prick, rapid tests can provide results in less than 30 minutes. If you give a blood sample through a syringe, then your doctor’s office will probably send it to a lab for testing. It generally takes longer to receive results through this process.

If you have the virus, it usually takes several weeks for your body to produce antibodies to it. Your body typically generates these antibodies four to six weeks after exposure to the virus. This means that an antibody test may not detect anything during this period. This is sometimes called the “window period.”

Receiving a positive ELISA result doesn’t mean that you’re HIV-positive. A small percentage of people may receive a false-positive result, which means the result says you have the virus when you don’t have it. This can happen if the test picks up on other antibodies in your system.

All positive results are confirmed with a second test. This is called the Western blot. This is a more sensitive antibody test. It can take up to a week for you to receive the results of this test.

What can affect your test results?

HIV tests are highly sensitive and may result in a false positive. A follow-up test can determine whether you’re truly HIV-positive. If you receive a positive result from a second test, you’re considered to be HIV-positive.

It’s also possible to receive a false-negative result, which means the result is negative when in reality you have the virus. This generally happens if you’re newly infected and you get tested during the window period. This is the time before your body has started producing HIV antibodies. These antibodies typically aren’t present until four to six weeks after infection.

If you receive a negative result and have reason to suspect that you’ve contracted HIV, you should schedule a follow-up exam in four to six weeks.

What you can do

If your doctor diagnoses you with HIV, your doctor will help you determine the best way to treat the infection. Treatments have become more powerful over the years, making the virus more manageable. You can start treatment right away to reduce or limit the amount of damage to your immune system.

You should also contact your sexual partners and alert them to any possible exposure. Encourage them to get tested.

If you receive a negative test result and you aren’t sure if it’s accurate, you should get retested. Your doctor can help you determine what to do in this situation.

How to prevent HIV transmission or infection

If you’re sexually active, you can take the following precautions to reduce your risk of infection:

  • Limit your number of sexual partners. Having multiple sexual partners increases your risk of exposure to the disease.
  • Use condoms as directed every time you have sex. If you use them correctly, condoms can prevent your bodily fluids from mixing with your partner’s fluids.
  • Get tested regularly. Ask your partner to get tested, too. Knowing your status is an important part of being sexually active.

If you think you’ve been exposed to HIV, you can go to your doctor to get post-exposure prophylaxis (PEP). This involves taking HIV medicine to reduce your risk of infection after possible exposure. You must start PEP within 72 hours of potential exposure.

Keep reading: 9 misconceptions you probably have about HIV/AIDS »

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