BLOG / New guidelines for HIV testing
Back in the day, everybody had to wait for three months from the time you may have been exposed to the HIV-virus to get a reliable test result. But not any longer.
The guidelines regarding HIV-testing were changed this spring by the Public Health Agency of Sweden. Research on HIV has come a long way, and the tools that detect HIV have become better. That motivated an update of the old guidelines:
- Ordinary lab test: 6 weeks after the risk of exposure
- Test with rapid test results: 8 weeks after the risk of exposure
- When suspecting the unusual HIV-2 infection: 12 weeks after the risk of exposure
If you are worried you have have contracted HIV, e.g., if you have symptoms of primary infection (fever, flue-like symptoms or a rash), a lab test can detect HIV in after only a couple of weeks.
The earlier the HIV infection is detected, the earlier treatment can start and suppress the virus. Starting treatment early makes a big difference in efficacy and overall health. The virus is more active in the beginning of the infection and has a higher probability to be transmitted to someone else during that period, unless safer sex is practiced.
So don’t wait in vain. Take control of your health. Take an HIV-test.
Why do I have to wait a certain number of weeks to get tested?
An HIV test usually detects antibodies to HIV in the blood. How long it takes for enough antibodies to develop varies from person to person. The Agency of Public Health have concluded that everybody has developed enough antibodies six weeks after transmission for HIV to be detected in a lab test. Eight weeks goes for the rapid test. That’s how long you may have to wait for at negative test result to mean that you don’t have HIV.
How early can HIV be detected?
Antibodies are the body’s defence against the HIV virus, and they are produced some time after the transmission of the virus. The lab test that is normally used in Sweden detects antibodies as well as antigen. Antigens are proteins on the surface of the virus, and they can be present in the blood in great quantities as early as a few weeks after transmission in a lab test. The rapid tests used in Sweden have no component for antigen detection, and for that reason they are not as suitable for early HIV detection.
What is hiv-2?
There are many variants of the HIV virus, and they are usually divided in two groups: HIV-1 and HIV-2. HIV-1 is common all over the world and is the variant that have been researched the most. HIV-2 exists in some areas of West Africa and isn’t transfered as easily between persons as HIV-1, which might explain why it hasn’t spread beyond those areas. For HIV-2, the guideline remains 12 weeks from the possible exposure.