HIV/Aids

Updated 26 June 2014

Testing for HIV

Having an HIV test? Dr Avron Urison explains what it is and how it works.

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Having an HIV test? Dr Avron Urison from AllLife explains what it is and how it works.
 

Many places provide private and confidential testing for HIV, both within the public and the private sector, which includes, for example:

  • Doctors rooms
  • Hospitals
  • Community health centres
  • Family planning clinics
  • Sexually transmitted disease clinics
  • Laboratories   

Most of these places provide free or inexpensive HIV testing. It is important to get tested at a place that also has HIV and AIDS counselling. Counsellors are often able to answer questions and help the individual understand what the test results mean.

How the test works

The HIV test detects the body’s response to HIV infection, by reacting with any antibodies that may have been produced, in response to HIV infection. This means that the test does not detect the virus itself.

Antibodies are special cells that your body creates in order to fight an infection and these will be specific to the infection. In the case of HIV, these will be HIV antibodies. After getting HIV, most people develop antibodies that can be seen within 3 months; the average time is 25 days after exposure to HIV.

 In rare cases, it can take up to 6 months to be able to see HIV antibodies. Because of this, an individual should get tested 6 months after their most recent possible exposure to HIV. If an individual has a test that is negative, it should then be repeated 3 months later, in case the person is in the ‘window period’ - the period during which the body may be producing antibodies to HIV.

Types of tests

Rapid tests are becoming increasingly popular in Africa, as they are highly reliable (over 99% accuracy), cost effective, and give the result within a short period of time - normally within half an hour. The patient may also be able to see the kit and the result. Either a small sample of blood (from a prick on the finger) or sample of mucous from the inside of the cheek or gums is taken, depending on the test. Should the test be positive, a confirmatory test would normally done, either using a different rapid test, or a sample of blood may be taken to carry out an ELISA (enzyme linked immunoassay) test.

The ELISA test was the standard used by many clinics before the advent of the rapid test. The patient’s blood is sent to a laboratory in a plain tube. Two separate specimens are tested using two different kits to confirm patient identity. The test result however is not immediate and results may take several days before the patient is given the results. This often places stress on the patient. In the event of the result being positive, a confirmatory test is done as with the rapid test above.

The Western Blot is used less in current testing environments. The test is labour intensive and can take longer than any of the other tests. It was frequently used as a confirmatory test if the patient had tested positive using the ELISA test.

(Dr Avron Urison, Medical Director at AllLife Pty Ltd - providers of life insurance for HIV positive individuals)

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Ask the Expert

HIV/Aids expert

Dr Sindisiwe van Zyl qualified at the University of Pretoria before working for an HIV/AIDS NPO in Soweto for many years. She was named one of the Mail & Guardian's Top 200 Young South Africans in 2012.

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