Anti-HIV antibodies

What is being analysed?
HIV, or human immunodeficiency virus, is the virus that causes AIDS (acquired immunodeficiency syndrome),
a disease characterised by destruction of the immune system, leaving the person susceptible to serious and debilitating infections. The test looks for anti-HIV antibodies in the blood, which are produced 2 to 4 weeks after exposure to the virus.

How is the sample collected for testing?
The blood test is carried out on blood taken from a vein.

How is it used?
When is it requested?
What does the test result mean?
Is there anything else I should know?

How is it used?
The anti-HIV antibody test is used to identify people infected with HIV. Early treatment of the infection and continuous monitoring of the immune system can ensure a relatively good state of health in the long term.
In addition, knowing your own HIV status can help you change your behaviour, reducing the risks for yourself and others.

Anti-HIV antibodies can be detected with an ELISA screening test, which is repeated if the result is positive. The ELISA test is very sensitive and, for that very reason, can give false positive results; a positive ELISA result must therefore always be confirmed with a Western blot test. These tests can be carried out in a hospital laboratory. Kits for taking the test at home, with the sample then sent to a specialist centre, have recently been approved. The results are then given by telephone, together with appropriate counselling. These tests are not yet available.

When is it requested?
The anti-HIV antibody test should be carried out on anyone who thinks they may have been exposed to the virus. In particular, the test should be done in the following situations:

• sexually active people (three or more sexual partners in the last 12 months)
• people who received blood transfusions before 1985, or partners of people who received transfusions and later tested HIV positive
• people who suspect risky behaviour by their sexual partner
• men who have sex with men
• people who inject drugs and share syringes
• people with other sexually transmitted diseases
• workers exposed to contact with blood
• pregnant women (treatment is now available that greatly reduces the risk of HIV being passed from mother to baby)
• women planning a pregnancy

What does the test result mean?
A healthy person does not have antibodies against HIV. If the test is positive for anti-HIV antibodies with both testing methods (ELISA and Western blot), the person must be considered infected with HIV.

Is there anything else I should know?
The anti-HIV antibody test cannot detect infection immediately after exposure to the virus: it is negative during the so-called “window period” between infection and the production of antibodies. A test done too early can give a false negative result. For this reason, repeating the test 3-6 months after the suspected exposure is extremely important to correctly identify infected people

1. What are the symptoms of HIV infection?
2. What are the symptoms of AIDS?
3. What is the treatment for HIV/AIDS?
4. Who can I talk to about the test result?
5. Can the anti-HIV antibody test be used to look for infection in newborn babies?
6. Apart from the blood test, are there other methods of testing for HIV?

1. What are the symptoms of HIV infection?
The only way to know whether you have been infected with HIV is to have the antibody test. In many people years can pass between infection and the first symptoms; moreover, these symptoms are often non-specific and similar to those of many other conditions.

2. What are the symptoms of AIDS?
The symptoms of AIDS are similar to those of other conditions.

3. What is the treatment for HIV/AIDS?
At present there is no treatment that can eradicate HIV infection or cure AIDS. However, there are treatments that can stop the disease progressing and limit or prevent symptoms, provided that treatment is started as early as possible.

4. Who can I talk to about the test result?
When a person tests positive for HIV, it is important that they receive correct information about the disease, the treatment options and how to protect the people they live with and/or their partner from possible infection. The family doctor can be the first point of contact, but there are community and hospital services where appropriate counselling is available.

5. Can the anti-HIV antibody test be used to look for infection in newborn babies?
The anti-HIV antibody test cannot be used to identify newborn babies infected with the virus. The mother’s antibodies can remain passively in the baby’s bloodstream for 6-12 months before disappearing. To diagnose infection acquired at birth, a test for viral DNA is therefore needed.

6. Apart from the blood test, are there other methods of testing for HIV?
Tests are now available to diagnose HIV infection from urine or other body fluids