Testing for HIV
It is important for a person to get an HIV test if they think they may have been at risk of HIV infection.
HIV testing should be voluntary and the right to decline testing should be recognized. Mandatory or coerced testing by a health-care provider, authority or by a partner or family member is not acceptable as it undermines good public health practice and infringes on human rights.
Some countries have introduced, or are considering, self-testing as an additional option. HIV self-testing is a process whereby a person who wants to know his or her HIV status collects a specimen, performs a test and interprets the test results in private. HIV self-testing does not provide a definitive diagnosis; instead, it is an initial test which requires further testing by a health worker using a national validated testing algorithm.
All HIV testing services must include the 5 C’s recommended by WHO: informed Consent, Confidentiality, Counselling, Correct test results and Connection (linkage to care, treatment and other services).
If you think you may have been exposed to HIV, get an HIV test. Most HIV tests detect antibodies (proteins your body makes against HIV), not HIV itself. But it takes a few weeks for your body to produce these antibodies, so if you test too early, you might not get an accurate test result. A new HIV test is available that can detect HIV directly during this early stage of infection. So be sure to let your testing site know if you think you may have been recently infected with HIV.
What kind of tests are there?
The Self test:
Rapid HIV diagnostic home-kit tests are available, but these tests should be used with extreme care. It is not advisable to do the home test without proper pre-test and post-test counselling. The results can also be incorrect if the testing instructions are not followed exactly, if the test has not been stored at the required temperature, if the expiry date of the test has been exceeded, or if tests of a low quality are used. A positive result obtained from a home test should always be confirmed by a subsequent laboratory test. HIV self-tests are already available in some pharmacies for about R 35.
The Rapid test:
A rapid HIV antibody test is a blood test, which can be done by pricking the finger with a lancet, and applying the test tube. The result is ready within 15 minutes.
Rapid tests are very useful for the diagnosis of HIV infection in rural or isolated areas that are far removed from diagnostic laboratories and where clients often cannot afford to come back for test results.
These tests are relatively cheap and they demonstrate a high rate of reliability if they are correctly used. The accuracy of rapid tests is variable but some tests are just as good as an ELISA test.
As with ELISA testing, the accuracy of a diagnosis of HIV infection using rapid tests is higher if two rapid tests both give a positive result. All positive rapid HIV results should, however, always be confirmed with a second rapid test (from another batch) or with a laboratory-based ELISA antibody test. A second confirmatory test will, however, not be necessary if a person presents with clear symptoms of immune depression.
The Elisa test:
Tests most commonly used to diagnose HIV infection are those that detect HIV antibodies. Two of the best-known HIV antibody tests are the ELISA (enzyme-linked immunosorbent assay) and the Western Blot tests.
Antibodies are small proteins made by your immune system whenever a new infection invades the body. HIV antibodies are present in the blood and in lower concentration in other body fluids such as saliva.
The best tests to detect HIV antibodies are the ELISA tests, which are extremely accurate in reacting to the HIV antibodies that are formed by the immune system in an unsuccessful attempt to protect the body against the virus.
HIV antibodies can usually be detected in the blood four to six weeks after infection. The antibody tests will therefore only become positive approximately six weeks after infection. (In some cases it may take much longer.)
The ELISA HIV antibody test is the most popular and commonly used test. It is widely available and reasonably cheap.
The ELISA test (as well as the Western Blot test) are laboratory tests, which means that blood must be drawn and sent to a laboratory where they use specialised equipment to test the blood. The results may therefore take anything from a day to a few days depending on where the test is done (in private practice in the city, or in a rural clinic where it has to be sent to a laboratory in the city).
The ELISA HIV antibody test is very sensitive and reliable, and produces very few false negative results. Because false positive results (where a test result is positive, while the person is actually HIV negative) can occasionally occur, an HIV positive test result should always be confirmed by means of a second test.
To make the diagnosis even more accurate, a sample that is found to test positive with one ELISA test will usually be re-tested with a second, different ELISA test.
Only if both tests are positive will you be regarded as being HIV antibody positive. Even then, it is recommended that a new blood sample be sent to the laboratory for repeat testing.
If this procedure is followed, then the accuracy of the diagnosis of HIV infection is very close to 100%. You are at high risk of transmitting HIV to others during this early stage, even if you have no symptoms. For this reason, it is very important to take steps to reduce your risk of transmission.