What does a negative test mean?
A negative antibody test does not guarantee that a person is HIV-negative. When a person is infected with HIV, antibodies begin to be made right away but it can take weeks to months from the time a person is infected until the time antibodies can be detected in the blood or other body fluids. During this time, the person may have a negative result on an HIV antibody test, even though she or he has been infected. For this reason, people who are no longer taking risks but who have had a recent history of any risky behavior should have two negative tests six months apart to be sure of the negative results. Even with negative antibody test results, people who participate in risky behavior should continue to refrain from donating blood, plasma, or semen for artificial insemination. They need to know that a negative test result does not mean that their risky behavior is safe. They may be found to be HIV positive at the next HIV test. Regardless of the positive or negative result of the test,
If your test is negative it might mean you are ‘in the clear for TB infection’ but it might also mean that you have been tested too early to find any reaction to the TB protein in the test. It will usually mean that you have not been vaccinated recently with the BCG vaccine so you might be offered a BCG vaccine. Sometimes, you will be offered repeat testing in a few weeks time – to double check that you are free of TB.
