Testing for Human Immunodeficiency Virus (HIV)

Human immunodeficiency virus (HIV) is the virus that causes acquired immunodeficiency syndrome (AIDS). Once HIV is in your body, it attacks the immune system. As the immune system weakens, it is less able to resist disease and infections.

AIDS is diagnosed when a person with HIV develops diseases that the immune system would normally fight off. These diseases include pneumonia, certain types of cancer, and harmful infections.

HIV is passed through contact with an infected person’s body fluids, such as semen, vaginal fluid, or blood. This can happen during sex or by sharing needles used to inject illegal drugs.

If you’re pregnant and have HIV, you can pass the virus to your fetus during labor. If you’re breastfeeding and have HIV, you can pass the virus to your baby.

If you are not infected with HIV but are at high risk of getting it, you can take medication to help prevent infection. This is called pre-exposure prophylaxis (PrEP). PrEP involves taking a daily pill or getting injections every 2 months. Along with other preventive measures, such as using condoms, PrEP may reduce your risk of getting HIV.

Read more: Preventing HIV With Medication

It’s important to be tested for HIV at least once in your lifetime. HIV testing is also recommended if you are pregnant or thinking about getting pregnant.

Unless you are tested, you may not know you have HIV until you get sick. Knowing your HIV status is critical for your health and the health of others. Early diagnosis and treatment with anti-HIV drugs can help you stay healthy for a long time and can decrease the chance of passing the virus to others.

You can get an HIV test from your obstetrician–gynecologist (ob-gyn) or other health care professional. You can also get an HIV test at special HIV clinics. You can find testing locations at https://gettested.cdc.gov.

There are three types of HIV screening tests:

• Antibody tests: These tests look for HIV antibodies in your blood or saliva. HIV antibodies can be detected 23 to 90 days after you are exposed to HIV.

• Antigen/antibody tests: These tests look for HIV antibodies and a specific HIV antigen called p24 in your blood. The p24 antigen can be detected 18 to 45 days after exposure.

• Nucleic acid tests (NAT): These tests look for the actual HIV virus in your blood. NAT tests are best if you know you have a recent exposure, but it is too soon to use another type of test. The virus can be detected 10 to 30 days after exposure.

There are also “rapid” HIV screening tests. With a rapid HIV screening test, results are ready quickly, usually within 1 hour. Rapid tests are usually antibody tests.

Your ob-gyn or other health care professional may offer rapid testing. Rapid tests may also be available at health clinics, local health department testing offices, hospitals, and community centers.

Home HIV screening kits test either a sample of saliva or a sample of blood that you get by pricking your finger. It is important to only use the home tests that are approved by the U.S. Food and Drug Administration (FDA) and to read the information that comes with the kit. You must do the test correctly to get an accurate result.

The test may not work until 3 to 6 months after you get HIV. The test result may be negative if you do the test before then.

Retesting is recommended each year if you have done any of the following since your most recent HIV test:

• Injected (shot) drugs
• Had a sex partner who injects drugs or has HIV
• Exchanged sex for drugs or money
• Had a male sex partner who has had sex with men
• Had more than one sex partner

You can be tested for HIV again at any time, even if you do not have risk factors. If you are older than 64 and you have risk factors for HIV, yearly retesting is recommended. It is also a good idea for you and your partner to be tested before starting a new sexual relationship.

A “reactive” or positive screening test result does not necessarily mean you have HIV. No matter what kind of screening test you have, you need a confirming test if you have a reactive or positive screening test result. Confirming test results take about 2 weeks. If the confirming test result is positive, you have HIV.

If your HIV test is confirmed, you have the virus and can pass it to others. A positive test result does not tell you whether you have AIDS or will get it.

If you have HIV, you should see a health care professional for treatment, even if you do not feel sick.

There are medications that can help people with HIV stay healthy for a long time. The earlier you start treatment, the better for your long-term health. Early treatment also reduces your risk of passing the virus to others.

Your health care professional will report your positive test results (but not your name) to your state health department. This is done to keep track of how many people in the United States have HIV.

All of your sexual partners and needle-sharing partners should know your HIV status so they can be tested and begin treatment if they are HIV positive. You can tell your partners yourself, or you can have the health department in your state do it. If you choose to have the health department tell your partners, your name will not be used when the partner is told.

Many states have laws that require you to tell your sexual partners and needle-sharing partners that you are HIV positive. You can learn more about sharing your HIV status at www.hiv.gov/hiv-basics/hiv-testing/just-diagnosed-whats-next/talking-about-your-hiv-status.

If you are pregnant and have HIV, the virus can be passed to your fetus. Getting treatment during pregnancy and treating the baby after birth can greatly reduce the risk of this happening. Getting treatment during pregnancy can also help you stay healthy.

If you are pregnant, you should have a routine test for HIV during your first prenatal care visit.

If you are at an increased risk of HIV infection, you should be retested in the third trimester of pregnancy, ideally before 36 weeks of pregnancy. You are at increased risk if you have any of the following risk factors:

• Have had a diagnosis of another sexually transmitted infection (STI) in the past year

• Inject drugs or have a sex partner who injects drugs

• Exchange sex for money or drugs

• Have a new sex partner or more than one sex partner during this pregnancy

• Have a sex partner who is HIV positive or at high risk of being HIV positive

You should also be retested in the third trimester if you have signs and symptoms of an HIV infection, including:

• Fever

• Swollen lymph nodes

• Skin rash

• Muscle or joint pain

• Headache

• Mouth ulcers (canker sores)

• Problems with your blood cells or liver

Retesting may also be recommended if you:

• Are in jail or prison

• Live or receive health care in an area that has a high number of people who are HIV positive

If you have HIV, the following steps can help prevent passing the virus to your fetus:

• Take anti-HIV medications during your pregnancy as prescribed.

• Have a cesarean birth if lab tests show that your level of HIV is high.

• Take anti-HIV medications during labor and delivery as needed.

• Give an anti-HIV medication to your baby after birth.

• Do not breastfeed.

By following these guidelines, 99 percent of people with HIV will not pass HIV to their babies.

If you were not tested for HIV during pregnancy, you should have a rapid HIV test when you go into labor. If this result is positive, you will need to have a confirming HIV test. While you are waiting for these results, you can receive anti-HIV medications during labor. The baby can receive anti-HIV medications in the first few days after birth.

Acquired Immunodeficiency Syndrome (AIDS): A group of signs and symptoms, usually of severe infections, in a person who has human immunodeficiency virus (HIV).

Antibodies: Proteins in the blood that the body makes in reaction to foreign substances, such as bacteria and viruses.

Antigen: A substance that can trigger an immune response and cause the body to make an antibody.

Cesarean Birth: Birth of a fetus from the uterus through an incision (cut) made in the woman’s abdomen.

Fetus: The stage of human development beyond 8 completed weeks after fertilization.

Human Immunodeficiency Virus (HIV): A virus that attacks certain cells of the body’s immune system. If left untreated, HIV can cause acquired immunodeficiency syndrome (AIDS).

Immune System: The body’s natural defense system against viruses and bacteria that cause disease.

Obstetrician–Gynecologist (Ob-Gyn): A doctor with special training and education in women's health.

Pneumonia: An infection of the lungs.

Pre-Exposure Prophylaxis (PrEP): Daily medication taken to help prevent infection with human immunodeficiency virus (HIV). Along with other preventive measures, such as using condoms, PrEP may reduce the risk of getting HIV.

Prenatal Care: A program of care for a pregnant woman before the birth of her baby.

Screening Test: A test that looks for possible signs of disease in people who do not have signs or symptoms.

Semen: The fluid made by male sex glands that contains sperm.

Sexually Transmitted Infection (STI): An infection that is spread by sexual contact. Infections include chlamydia, gonorrhea, human papillomavirus (HPV), herpes, syphilis, and human immunodeficiency virus (HIV, the cause of acquired immunodeficiency syndrome [AIDS]).

Trimester: A 3-month time in pregnancy. It can be first, second, or third.