An article on HIV home test kits (March 18) stated that HIV testing needs to be done six months after the risky exposure. This is a popular misconception and gives rise to unnecessary anxiety.

The facts are that most people seroconvert, that is, show a positive blood result four to six weeks after infection. However, it can take up to 12 weeks - the so-called window period. This is why we insist that blood tests should be done at presentation and repeated at the 12-week stage to be absolutely sure of the result. Exceptionally, the test is repeated at six months if the patient had been exposed to someone definitely known to be HIV positive and/or if the index patient had been put on prophylactic anti-HIV therapy.

I stress, however, that this is not required for routine purposes.