What is the "window" period in HIV testing?

The article was professionally consulted by Specialist Doctor I Huynh Kim Long - Emergency Resuscitation Doctor - Emergency Resuscitation Department - Vinmec Danang International Hospital

When there is a negative HIV test result, the patient should still test again after 1-3 months to avoid the test result being a false negative, HIV testing during the window period gives negative results despite the fact. is infected with HIV.

Test for antigens (part of the virus) Tests for antibodies to the HIV virus. This antibody is made by the body of an HIV-infected person to fight the HIV virus. Or you can test for both antigens and antibodies. However, it can take about 2 weeks for the antigen to be detected in the body by testing and more than 3 weeks for the body to make enough antibodies. In a small number of people, this process can take up to several months.

Because it takes time for the body to make antibodies and a new time to detect HIV antigens. There should be the concept of "Window period".
The window period in HIV testing is the time between being infected with HIV (when the virus enters the body) and HIV detection by tests. At this time, the test will give a negative result while the person taking the test is already infected with HIV. However, HIV tests are now increasingly narrowing this time frame and reducing the chance of a false-negative result - that is, actually having HIV but the result is negative.

A negative HIV test has two cases: true negative and false negative.

When the result is negative (Negative), this means that the person testing is not infected.

In rare cases, the negative result is not true (false negative), it means that the patient has HIV but the test results show that the person does not have HIV.
HIV window test will give false negative results. The person's body was infected with the HIV virus, but the body had not yet produced antibodies against the HIV virus, so the test was negative.
In case of exposure to a risk factor but when the test is negative, a repeat HIV test in 1-3 months later is necessary to ensure HIV infection or not because it is most likely timing Testing is in the window period.

During the window period, despite having a negative test, the virus has actually entered the body and is multiplying and developing strongly. So even during the window period, an infected person can still transmit HIV to others.
Because it is possible to infect others, even if the test result is negative, the patient still needs to actively prevent and use protective measures for those around during this time.
If you experience or do not have the above symptoms, you should still be screened for social diseases for early detection to have effective treatment and avoid complications. Vinmec International General Hospital currently has a Social Disease Screening Package, which helps to most accurately detect social diseases, including syphilis. The examination package is carried out with the participation of a team of highly qualified and experienced medical doctors, optimal facilities system and commitment to ensuring privacy for customers when visiting.