HIV test

An HIV test checks a sample of your blood to see if you are infected with HIV (human immunodeficiency virus). HIV is a virus that destroys certain cells in your immune system. These cells protect your body from diseases caused by germs, such as bacteria and viruses, as well as fungi. If you lose too many immune cells, your body will have a hard time fighting off infections and other illnesses.

HIV is spread through contact with the blood and other body fluids of a person with HIV infection. This usually happens during sexual intercourse or when sharing syringes or other objects used to inject drugs.

HIV is the virus that causes AIDS (acquired immunodeficiency syndrome). AIDS is the last and most serious stage of HIV infection. Without treatment, HIV gradually destroys your immune system, leading to AIDS. With AIDS, your body has a hard time fighting infections caused by germs that don't usually cause problems in healthy people. These infections are called opportunistic infections, and they can be fatal. AIDS also increases your risk of developing certain cancers.

Most people living with HIV do not have AIDS. If you have HIV and take HIV medication as prescribed, you may never develop AIDS. Getting tested for HIV helps detect the virus early so you can start treatment, stay healthy, and avoid spreading HIV.

If you think you have been exposed to HIV, talk to your health care provider right away about emergency treatment, called PEP (post-exposure prophylaxis). The PEP can warn an HIV infection if it is started within three days of a possible exposure. The sooner you start the better. You will need to get tested for HIV during and after taking PEP.

There are three main types of HIV tests. They are all very accurate, but no test can detect HIV in your body immediately after infection. This is because it can take weeks before the signs of HIV in your body increase enough to show up on a test. The time between infection and when a test can detect HIV depends on your body's response to HIV and what type of test you have:

• HIV antibody tests Look for HIV antibodies in your blood, saliva, or urine. HIV antibodies are proteins that fight diseases that your immune system produces when you have an HIV infection. Some people make antibodies more quickly than others. An antibody test can detect HIV antibodies as early as 23 days after infection, but may take up to 90 days before your body produces enough antibodies to show up on this test.
  
  Antibody tests can be done in a number of ways:
  • Laboratory tests use a blood sample taken from a vein. In general, lab tests can detect antibodies sooner after infection than other HIV antibody tests. Test results are usually ready a few days after your blood sample is taken.
  • Rapid tests use blood from your finger, saliva, or urine They provide results in about 30 minutes.
  • Home tests include do-it-yourself rapid test kits with everything you need to collect and test a saliva sample by yourself. With correspondence tests, you take a drop of blood from your finger to send it to a laboratory for analysis.
• HIV antibody/antigen tests are the most commonly used HIV tests. They're looking for HIV antibodies and antigens in your blood. An antigen is the part of the HIV virus that triggers your immune system to fight infection. After exposure to HIV, antigens will appear in your blood sooner than antibodies:
  • Laboratory tests who use a blood sample taken from a vein can detect HIV infection as early as 18 to 45 days after infection.
  • Rapid tests use a drop of blood taken from your finger. This test can detect HIV infections from 18 days to 90 days after infection
  • Home tests, or correspondence tests, allow you to take blood from your finger at home and send it to a laboratory for analysis. Like rapid tests, these tests can start to detect HIV. 18 to 90 days after infection
• NAT tests (nucleic acid tests) look for HIV in a sample of your blood taken from a vein and tested in a lab. These tests may also be referred to as “viral load tests.” They can usually detect HIV infection as early as 10 to 33 days after infection. But they're mostly used to monitor HIV treatment and not for routine testing because they're expensive. Ask your health care provider to do a NAT test as soon as possible if you:
  • You think you have been exposed to HIV and have symptoms, such as:
    • Flu symptoms including fever, chills, pain
    • Extreme tiredness
    • Swollen lymph nodes (in your neck, groin, or armpit)
    • Skin rash
    • Sores in your mouth
  • You know that you have

An HIV test is used to determine if you have been infected with HIV. It can be done as a routine test or after possible exposure to find out if you have been infected with HIV.

If HIV is detected early, you can take medication to protect your health so as not to develop AIDS. And medications can help you avoid transmitting HIV to others.

The Centers for Disease Control and Prevention (CDC) recommends that everyone between the ages of 13 and 64 get tested for HIV at least once as part of routine health care.

You may need to get tested more than once if you have a higher risk of infection. If your last HIV test was more than a year ago, you should get tested as soon as possible if you have:

• Having had vaginal or anal sex with someone who has HIV (HIV positive) or whose HIV status you don't know
• Having injected drugs and shared needles, syringes, or other drug-related items with others
• Exchanging sexual relations for money or drugs
• Have had a sexually transmitted disease (STD), such as syphilis
• Having had sexual relations with anyone who did any of the things listed above

If you do any of the things on the list above regularly, you should get tested for HIV at least once a year. Some people, including men who have sex with men (MSM), may benefit from more frequent testing, depending on their risk. Ask your provider how often you should be tested.

If you are pregnant, your doctor may order an HIV test. This is because HIV can be transmitted to the baby during pregnancy and birth, and through breast milk. There are medications you can take during pregnancy and birth that greatly reduce your risk of transmitting HIV to your baby.

You do not need any special preparations for an HIV test. If you are being tested at a health clinic or community program, a counsellor can discuss your HIV risk with you. So, you might want to write down any questions you have in advance.

There is very little risk in getting tested for HIV. If you have blood drawn from a vein, you may feel a slight pain or bruise where the needle was inserted, but most symptoms go away quickly.

A negative test result means that no signs of HIV infection were found in your sample. But that doesn't always mean you don't have HIV. You may have an HIV infection, but it is too early for the test to detect it and you may need another test later. Your HIV provider or counsellor can explain your test result and let you know if you need another test.

In general, if you have a Negative result On a rapid test Or a home test and a possible exposure to HIV which was:

• 90 days or more ago, you can be sure that you don't have HIV
• Fewer than 90 days ago, you will probably need another test later to check for HIV again

A positive test result means that signs of HIV infection have been found in your sample You will need a follow-up test to confirm an HIV diagnosis unless you have had a NAT test.

• If you used a home test, consult your provider for a follow-up test.
• If you took your test in a medical office or community program, the test site will organize your follow-up test.

If your follow-up test is also positive, that means you have HIV. It is important to start medications called antiretroviral therapy (ART) right away, even if you are still healthy. ART cannot cure HIV, but it can reduce the amount of virus in your blood to the point where a test can't detect it. If you are living with HIV, it is important to see your provider regularly for tests to see how your treatment is working.

Learn more about lab tests, reference ranges, and understanding results.

The HIV test can be anonymous. This means that you do not have to give your name when taking an HIV test. Instead, you will be given a number. To get your test results, you'll give the number instead of your name.

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