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HIV testing
There are three main types of HIV tests.
The first type of test is the HIV antibody test.
This test shows whether a person has been infected with HIV, the
virus which causes AIDS. The second type of test is P24 antigen
testing. It is primarily used to screen the blood supply but in some
places it is used for testing for HIV in individuals. P24 antigen is
a protein that is part of the HIV. In the early stages of the HIV
infection, it is produced in excess and can be detected in the blood
serum by a commercial test. The P24 test can detect HIV infection
before the HIV antibody test can. Therefore, P24 antigen testing is
used in diagnosing HIV early in the course of infection. The third
type of test is used when a person knows that she or he is already
infected with HIV. These tests show the level of virus in the blood
(viral load test).
The HIV test looks for antibodies in a person's
blood. When HIV enters a person's body, antibodies are produced,
which are the body's special chemical response to an infection. So
if a person has antibodies to fight HIV in their blood, it means
they have been infected with HIV (an exception is the case of an HIV
negative baby born to a positive mother, who will retain her
antibodies for some months). For most of the people it normally
takes about 3 months to develop antibodies. In the rarest of rare
cases, it can take up to maximum 6 months. It would be extremely
uncommon to take longer than 6 months for antibodies to develop.
Getting tested earlier than 3 months may result in
an unclear test result, as an infected person may not yet have
developed antibodies to HIV. The time period between infection and
the development of antibodies to the infection is called the window
period, the period in which people infected with HIV have no
antibodies in their blood that can be detected by an HIV test.
However, it might be true that the person may already have high
levels of HIV in their blood, sexual fluids or breast milk and can
get transmitted to another person during this window period.
Although, an HIV test will not show that the person is infected with
HIV, therefore, the best policy is to wait for at least three months
after the last time you were probably at higher risk level before
taking the test. Some test centers may recommend re-testing again
after another 6 months have passed, in order to be extra cautious in
this regard.
It is also crucially important here, that, you are
not at any further risk and get infected with HIV during this time
period. The test is only accurate if there are no further incidental
exposures between the time of possible exposure to HIV and time of
testing. The only way to know for sure whether you are infected with
HIV is to have an HIV antibody test. It is just not possible to tell
from any symptoms without proper diagnostic test. |
