Getting a Human Immunodeficiency Virus (HIV) Diagnosis

Human immunodeficiency virus (HIV) is diagnosed using one of three types of tests: nucleic acid, antigen/antibody, and antibody tests. These tests may use either a sample of your blood or saliva to get results. A healthcare provider can also use a urine sample. No test can detect the virus right after exposure. The window for how early a test can detect HIV after exposure depends on the test and varies anywhere from 10 to 90 days.

HIV is a virus that attacks white blood cells (called CD4 cells) in the immune system. These cells help your body fight infections. HIV kills CD4 cells, causing your immune system to weaken and become vulnerable to other illnesses.

Getting tested for HIV is the only way to diagnose HIV. HIV can cause damage to the immune system and lead to acquired immunodeficiency syndrome (AIDS) if untreated. Knowing your HIV status can get you started on treatment sooner, help you reduce symptoms, and stabilize the spread of HIV in your immune system.

You can get a test for HIV at a healthcare provider’s office, family planning clinic, pharmacy, mobile testing van, or during HIV/AIDS awareness-related community events. At-home HIV tests are also available for pick-up or purchase in some pharmacies and clinics. These places can connect you to specialists who provide HIV care, knowledge about treatment options, and other social services if you receive a diagnosis or a positive test result.

Who Should Get Tested for HIV

Experts advise that HIV testing be a part of everyone's routine healthcare screening, including people who are pregnant. The Centers for Disease Control and Prevention (CDC) recommends that anyone aged 13–64 get tested for HIV at least once. You'll want to get tested for HIV if you have symptoms of acute or chronic HIV. 

Not everyone experiences HIV symptoms, which can mimic flu-like symptoms. Healthcare providers recommend frequent testing (i.e., at least once a year) for people who participate in behaviors that increase their risk of acquiring HIV.

These behaviors include:

• Being a man who has sex with another man
• Engaging with more than one sexual partner 
• Having sex with someone who is HIV positive
• Having unprotected vaginal and anal sex
• Receiving a separate diagnosis for sexually transmitted infection (STI), hepatitis, or tuberculosis 
• Sharing of needles, syringes, or other drug injection equipment

Getting tested after taking part in these activities is important. Testing can detect HIV early and help you get started on treatment sooner.

If you think you have been exposed to HIV, talk to your doctor about post-exposure prophylaxis (PEP). PEP is an HIV medication that works to keep the virus from settling in your body and is taken within three days of potential exposure. Note that PEP is not meant to be taken regularly and should be utilized in emergency situations only.

Types of HIV Tests

HIV carries an antigen called protein 24, or just "p24." Antigens are foreign substances that enter your body and send a signal to your immune system that there is something wrong. The immune system begins to produce antibodies (proteins that help fight the virus) when your body is exposed to HIV.

A healthcare provider can offer you three tests: an antibody test, an antigen/antibody test, or a nucleic acid test (NAT). The p24 antigen shows up in HIV tests faster than the antibodies that your immune system makes to fight the antigen. A healthcare provider may give you more than one test to confirm an HIV diagnosis.

Each test has a different window period. A window period is the time between when you get the virus and when an HIV test can accurately detect that you have the virus. HIV tests cannot detect HIV right after you think you may have been exposed to the virus. The earliest an HIV test can detect the presence of the virus is 10 days.

Antibody Test 

An HIV antibody test uses a sample of your blood, saliva, or urine to check for HIV antibodies. Most rapid HIV tests and at-home self-tests are antibody tests. This test can detect HIV antibodies 23–90 days after exposure to the virus. It takes about 30 minutes to get your results from a rapid antibody test.

Antigen/Antibody Test

An HIV antigen/antibody test looks for the presence of both HIV antigens and antibodies in your immune system. This lab test involves drawing blood from a vein. An antigen/antibody test can see if you have the virus 18–45 days after exposure to HIV.

A traditional antigen/antibody lab test result may take several days. Rapid antigen/antibody testing is also available. You can get a blood sample from a finger stick rather than your vein. The window periods and result times between rapid and traditional HIV antigen/antibody tests are different.

A rapid test has a longer window period than a traditional test and can detect the virus 18–90 days after HIV exposure. Results from a rapid antigen/antibody come faster than a traditional test. You can get rapid results in less than 30 minutes via a finger stick test.

Nucleic Acid Test (NAT)

A nucleic acid test (NAT) looks for HIV in the blood. A healthcare provider takes a blood sample from your vein. They will send the sample to a lab for proper testing. NAT results can show whether or not you have HIV and your viral load (how much of the virus is in your blood).

NAT has a quicker window period than other types of HIV tests. You can get a NAT test 10–33 days after exposure to the virus. It may take several days to get your lab test results back. One more thing to keep in mind: this type of test is most appropriate for people who may be showing symptoms of acute HIV and have tested negative with antibody or antibody/antigen tests.

Stages of HIV 

HIV moves through three stages, which include:

• Acute HIV stage: The first stage of HIV begins two to four weeks after a person acquires the virus. Most people in the acute stage experience flu-like symptoms. 
• Clinical latency (chronic HIV) stage: The second stage of HIV can begin as soon as one month after exposure to the virus and last between 10–15 years. Some people in this stage don't experience symptoms. The virus also continues to multiply at low levels in the immune system if you are not receiving HIV treatment.
• AIDS stage: The third and final stage of HIV typically occurs in people who are not receiving treatment. Without treatment, the virus will continue to multiply and weaken the body's immune system. You may experience severe symptoms such as rapid weight loss, pneumonia, and swollen lymph nodes. You are also at an increased risk of developing serious infections and cancers.  

HIV symptoms and how fast (or slow) you move into a different stage of HIV vary from person to person. Your HIV progression can depend on your individual symptoms, whether or not you are on treatment, and your overall health. 

A Quick Review

HIV is a serious chronic condition that attacks healthy white blood cells (CD4 cells) in your immune system, which can prevent your body's ability to fight off infections. There is no cure for HIV, which is why getting HIV might feel scary. It's OK to be nervous, but it's also important to know that getting an early diagnosis can get you started on treatment sooner. 

The only way to know your HIV status is to get an HIV test. An HIV test will use a sample of your blood (from a vein or finger stick), saliva, or urine. There are three types of HIV tests: the antibody test, the antigen/antibody test, and the nucleic acid test (NAT). You can receive your results within 30 minutes or up to several days, depending on the type of test you take.

Getting an HIV diagnosis can be life-changing and filled with many emotions. Healthcare providers and other care specialists are there to help guide you through a positive HIV test result and the early stages of an HIV diagnosis. A healthcare provider can also help you create a treatment plan that is right for you, which can help you live a long and healthy life with your condition.