When you get tested for a condition like human immunodeficiency virus (HIV), you likely understand the meaning of results that are positive (yes, you have it) or negative (no, you don’t). But what does a “nonreactive” HIV test result mean? That might be less clear.
An HIV test is used to find out if you are infected with HIV, and a nonreactive result means that the test did not detect signs of HIV in the fluid sample you provided. Although this news usually is reassuring, suggesting that you’re not living with HIV, it’s also possible that testing was done too soon after infection to register a positive result.
Understanding your HIV test is important to make sure you know whether you need treatment and if you could pass the infection on to others. It can be confusing if you are told that your HIV test is nonreactive instead of negative, so read on to learn more about what a nonreactive test result means.
To get the most accurate result, it’s important to avoid taking an HIV test too early after a possible exposure. It’s best to get tested after the window period for the type of test you are taking.
The window period is the time between a possible HIV exposure and when an HIV test can accurately detect an HIV infection in your body. The length of the window period depends on the type of test you take and may fall somewhere within 10 days to 90 days after exposure. This means that a test might find an HIV infection as early as 10 days but could take up to 90 days to accurately detect an infection.
Three types of HIV tests available — antibody tests, antibody/antigen tests, and nucleic acid tests (NATs). Each test looks for a different indicator of an HIV infection.
Talk to your health care provider about which test is right for you.
An antibody test checks for HIV antibodies in a sample of body fluid. The sample is most commonly blood or saliva, but some urine tests are also available, depending on the type of test. Your doctor can use an antibody test to test you for HIV while you wait (a rapid test) or send a blood sample (taken from your vein) to a laboratory. You can also find at-home HIV antibody test kits.
Antibodies are proteins your immune system makes to help recognize and fight foreign invaders, such as viruses. If you are infected with HIV, your body will make antibodies to specific parts of the virus called antigens. You won’t have HIV antibodies immediately after being infected because it takes time for your body to recognize HIV antigens and start producing antibodies. In general, antibody tests with a blood sample can detect HIV earlier than a saliva or urine sample. The window period for an HIV antibody test is between 23 and 90 days after infection.
If you have a nonreactive HIV antibody test, it means that the test was not able to detect HIV antibodies in your fluid sample. This test may not accurately diagnose HIV if you take it before your body begins making antibodies.
Antibody/antigen tests check for both HIV antibodies and antigens in your blood. These are the most commonly used types of HIV tests, and they’re available as rapid tests and laboratory tests.
This type of test may provide an accurate result earlier than antibody tests because HIV antigens can show up in your blood sooner than your body can make antibodies. The window period is 18 to 90 days for a rapid antibody/antigen test and 18 to 45 days for an antibody/antigen laboratory test.
A nonreactive antibody/antigen test means that the test did not detect HIV antibodies or HIV antigens in your blood sample.
Also known as viral load tests, NATs look directly for HIV and can tell how much of the virus is in your blood. This type of test is most often used to monitor HIV treatment. NATs require sending a blood sample taken from your vein to the laboratory for testing.
NATs can often detect an HIV infection earlier than other tests because they detect particles of the virus itself. The window period for NATs is between 10 and 33 days after infection.
Although this test may be able to detect infection a few days earlier than others, it isn’t commonly used as a screening test. Your medical provider may order a NAT if you have had a nonreactive antibody or antibody/antigen test but are showing early symptoms of HIV, such as fever, chills, or swollen lymph nodes. Your medical provider will likely order a NAT every three months as part of your HIV screening if you are taking preexposure prophylaxis (PrEP) — regular testing helps make an early diagnosis if HIV should occur. If antigen/antibody testing shows initial reactive results, the lab may also run a NAT to confirm whether HIV can be detected.
The Centers for Disease Control and Prevention (CDC) recommends that everyone between ages 13 and 64 be tested for HIV at least once. If you have certain risk factors, you should get tested more often.
According to the CDC, people with the following high-risk factors should be tested at least once per year:
According to the CDC, if you’re a sexually active gay or bisexual man, it may be beneficial for you to be tested more often — every three to six months. Talk to your doctor about your risk factors and how often you should be tested.
Your health care provider can explain your HIV test results and go over your risk factors for HIV infection. If you took the HIV test before the window period was over, you might need to retest. If you took the test three months or more after a possible HIV exposure, you can be confident you are not infected with HIV.
If you know or suspect you have been exposed to HIV, you should ask your doctor about starting post-exposure prophylaxis (PEP) to reduce your risk of an HIV infection. PEP should begin within 72 hours (three days) of exposure and can be started before an HIV test can detect an infection.
You should also continue to take steps to prevent the spread of HIV, such as:
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Have you received a nonreactive result for an HIV test? Did you discuss the result’s meaning with your health care provider? Share your experience in the comments below, or start a conversation by posting on your Activities page.