There are three main types of HIV test.

The first type of test is the HIV antibody test. This test shows whether a person has been infected with HIV, the virus that causes AIDS. Information on this page concentrates on HIV antibody testing.

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. P24 antigen is a protein that is part of the HIV. Early in the 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 test 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). More information about viral load can be found on the AVERT website at www.avert.org.uk

The HIV test looks for antibodies in a person's blood. When HIV (which is a virus) enters a person's body, a special chemical is produced. These are called antibodies. Antibodies are the body's response to an infection. So if a person has/ develops antibodies to HIV in their blood, it means they have been infected with HIV.

For most people it takes 3 months for these antibodies to develop. In rare cases, it can take up to 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 between infection and the development of antibodies is called the window period. In the window period people infected with HIV have no antibodies in their blood that can be detected by an HIV test. However, the person may already have high levels of HIV in their blood, sexual fluids or breast milk. HIV can be passed on to another person during the window period even though an HIV test will not show that you are infected with HIV. So it is best to wait for at least three months after the last time you were at risk before taking the test. Some test centres may recommend testing again at 6 months, just to be extra sure.

It is also important that you are not at further risk of getting infected with HIV during this time period. The test is only accurate if there are no other exposures between the time of possible exposure to HIV and testing.

The only way to know for sure whether you are infected with HIV is to have an HIV antibody test. It is not possible to tell from any symptoms.

Many people who have an HIV test have been worrying unnecessarily. Getting a negative result (which means you are not infected with HIV) can put your mind at rest. If your test result is positive, many things can be done to help you to cope with the HIV positive result and look after your health. If your test is positive, then:

• A doctor can keep an eye on your health. Many people who test positive stay healthy for several years. But if you fall ill, there are many drugs called antiretrovirals that can help to slow down the virus and maintain your immune system. You can also have medicines to prevent and treat some of the illness that people with HIV get. You may also have access to trials of new drugs and treatments.

• If you do fall ill, the doctor is going to take your symptoms more seriously if they know that you are HIV positive.

• If you know that you are HIV positive, you can take steps to protect other people. For example, by practising safe sex and informing you past sexual partners.

• Knowing that you have HIV may affect some of your future decisions and plans, for example starting a family.

More information about learning that you are positive can be found on the AVERT website.

In most countries, there are many places that you can get tested for HIV. It is recommended that you get the HIV test done at a health clinic, at the doctors, or at a specialist HIV/AIDS voluntary counselling and testing (VCT) site. When you attend to get tested, you will see a doctor, trained counsellor, a nurse or some other health professional in private. He or she will explain what the test involves and what the result means. Normally a small sample of blood will be taken from your arm, sent to a laboratory and tested.

The test is always strictly confidential and only goes ahead if you agree. Your personal doctor will not be told about the test without your permission. Depending on the test used, it can take anything from a few days to a week or longer to get the result back.

A rapid HIV test is also an antibody test. The advantage of a rapid test is that you do not have return to get your test result. The test results from a rapid test are usually available in approximately 30 minutes. Rapid tests are single-use, and do not require laboratory facilities or highly trained staff. This makes rapid tests very suitable for use in resource-limited countries. More information about voluntary counselling testing in resource-poor communities can be found on the AVERT website.

It is generally recommended that the HIV test is done in a health care setting. However, in some countries 'home sampling' test kits are available. With a home sampling kit, a person can take a sample (usually a blood sample) and then sent it off to a laboratory for testing. A few days later, the person phones up a special number, gives their individual identification code, and is then given the result over the phone. If the result is positive a professional health specialist will provide emotional support for the person. For 'home sampling', the major advantages are convenience, speed privacy and anonymity. In countries where HIV tests are not free, home sampling may be a cost-effective way to get tested. But for some people the lack of face-to face counselling before and after the test may be a disadvantage. There is one company in the USA that offers an FDA approved 'home sampling' test kit for HIV. In the UK, the sale of any type of HIV testing kit for private use is illegal.

An instant HIV test kit means that the results are learned on the spot without any counselling. These kinds of tests are not generally recommended in any case because of their lack of accuracy and emotional support for the person. At present, this kind of test cannot be legally sold in many countries.

This page has so far contained some factual information about HIV and different types of tests. But testing is also about the lives people lead, and the personal views they hold, as Jenny explains below.

Hi, I am a 30 year old heterosexual woman and I currently have no children. I am not an intravenous drug user or a haemophilic. However, I have had unprotected sex with a number of heterosexual men. I know this behaviour can produce deadly results and I have had 2 negative HIV tests in the past 10 years with the last one being in 1996. Since my last HIV test I have had unprotected sex 5 times.

I hadn't recently given the subject much thought until I received notice that a local family had contracted HIV. I started thinking about my behaviour and how I have been gambling with my life and also putting the lives of others at risk, since I did not know my current status. I have been blessed with two prior negative HIV results. For the past two weeks I have been reading articles on HIV/AIDS, reading the stories of women who have contracted the virus and are courageously battling the disease, and also reading the signs and symptoms. I have prayed for guidance and for a repeated chance to begin a new pattern in my life if only my test would come back negative just one more time.

This morning I went for another HIV test and, thank god, it came back negative. I urge everyone black, white, gay, and straight to be tested. I also want to thank the women, men and children who have contributed their stories to this site. I must have read your words a thousand times over. You have made a difference in my life.

Signed Jenny in America

Norfolk has three Genito-Urinary Clinics (GUM Clinics) in three major locations providing a confidential specialist service including information, advice, counselling, testing for and treatment of sexually transmitted infections including HIV. They are the:

Grove Clinic in Norwich:
Department of Genito-Urinary Medicine
Norfolk and Norwich University Hospital
West Block, Level 3 (Outpatients)
Colney Lane, Norwich NR4 7UJ. Tel : 01603 286307/8

Bure Clinic in Great Yarmouth:
Dept. of Genito-Urinary Medicine
James Paget Healthcare NHS trust
Lowestoft Road, Gorleston-on-Sea, Great Yarmouth.
Tel : 01493 452747

Dept of GUM in King’s Lynn:
Queen Elizabeth Hospital, Gayton Road, King’s Lynn
PE 30 4ET
Tel: 01553 613766

GUM Clinics are completely confidential outside of the obligation to break confidentiality if someone’s safety were at serious risk - you don’t even have to give your real name if you don’t want to. The services are open access - no referral is needed.

To mark World AIDS Day 2004 the Norfolk NHS HIV and Sexual Health Unit is launching a campaign to raise awareness about nature and availability of HIV tests in the county.