Diagnosis of Hiv Aids - How to do it

The most common, cost-effective, and accurate method of diagnosing HIV infection is via a blood test that looks for antibodies to HIV. Antibodies are the body's reaction to HIV and other foreign substances. Other methods that can be used are rapid HIV antibody tests that use blood, saliva, or urine. The Food and Drug Administration (FDA) approve all of the above methods.

Before an HIV test can be performed a trained HIV counselor will discuss the test, how to understand its results, and what effect testing will have on your life in detail. You will also be asked to give written permission to be tested.

When someone is tested for HIV, a test called an Enzyme-Linked ImmunoSorbent Assay, or ELISA,

 is performed using a sample of blood obtained from a patient’s vein. If this test is positive a second test called a Western Blot is done, on the same sample of blood, to confirm the positive test. A Western Blot is a blood test to detect antibodies to several specific components of a virus such as HIV. If the initial ELISA test is negative then no further testing is done on that sample, although there are some exceptions to this. Sometimes a test result may be described as “inconclusive”. This means that a diagnosis cannot be made on this sample. It is usually recommended that another sample should be obtained and the test repeated.

The HIV antibody test has limitations. Antibodies to HIV are not made immediately and sometimes can take up to 3 months to develop (the window period). Therefore a negative test does not necessarily rule out a recent infection. If you have had a recent exposure you may need to be retested after 3 months to obtain an accurate result. In a research setting a HIV PCR or viral load test might be performed to detect a recent infection.

Similar antibody tests can be performed using Rapid EIA (ELISA) test on a saliva or blood specimen. This kind of test has been shown to be highly accurate (99.5%) This is comparable to the blood tests mentioned above that are performed in a lab. A positive result from a Rapid EIA test ia considered preliminarily positive and must be confirmed with an ELISA and Western Blot performed in a lab. Results are usually available in 20 minutes.