What Is an HIV Test?

What to Expect Before, During, and After the Test

A lab technician performing a rapid HIV blood test.
A lab technician performing a rapid HIV blood test.

Martin Harvey/Getty Images

An HIV test is used to determine if you have been infected with the human immunodeficiency virus (HIV). While the test is commonly performed on a blood or saliva sample, a newer urine-based test was approved for use in the United States in 2015. 

There are both indirect and direct methods of HIV detection. Indirect methods do not detect the virus but rather proteins, called antibodies, that are produced by the immune system in response to the virus. Direct testing methods detect either antigens (proteins on the surface of the virus) or RNA (the virus’ genetic material).

There is also different testing options, ranging from point-of-care tests used in clinics to rapid oral tests used at home. While the tests are extremely accurate if used correctly, they can return a false-negative result if you test too soon after an exposure.

Purpose of Test

There are an estimated 1.2 million people living with HIV in the United States, 25 percent of whom remain undiagnosed. Each year, an additional 50,000 people are infected.

In response, the U.S. Preventive Services Task Force has issued updated guidance recommending that every American between 15 and 65 undergo once-off HIV testing as part of a routine doctor visit. Testing is also recommended for pregnant women to avoid passing the virus from mother to child.

Annual or even biannual tests may be advised for people at a high risk of infection, including:

Types of HIV Test

There are different methods of HIV testing which vary in their speed, accuracy, and ease of use.

  • Rapid point-of-care tests can deliver preliminary results in around 20 minutes. Depending on the test being used, it may involve a blood drop from your finger, an oral swab from your gums, or a sample of urine. Of these, the preferred method is the blood-based combination HIV antigen/antibody (Ag/Ab) test.
  • Standard point-of-care tests are lab-based tests which detect HIV antibodies only. Also known as the HIV ELISA, the test requires a blood draw. The results are usually returned within five to 10 working days. The test is less commonly used today and has been largely replaced by the combination HIV Ag/Ab test.
  • Rapid at-home tests are saliva-based antibody tests that can be purchased online or at many retail drugstores. While less accurate than a point-of-care test, the test offers privacy and can deliver results in around 20 minutes.
  • Home collection kits can also be purchased online. This antibody test requires a drop of blood on a test card, which you would send to a lab via express mail. You can then receive the results either by phone or online as early as the next business day.
  • Nucleic acid tests (NAT) are blood-based tests used for early diagnosis that detect HIV RNA. While expensive, the NAT can detect HIV earlier than other forms of testing and may be appropriate if you have had a recent high-risk exposure or are experiencing acute symptoms of early infection. The NAT is also used to screen donated blood or test newborns suspected of having HIV. Results are usually returned within a couple of days.

Any positive result—called the preliminary positive—would require a second confirmatory test to ensure the diagnosis is correct. The only exception is the NAT which does require confirmation.

Test Accuracy

HIV tests are highly accurate if used correctly. With that being said, some testing methods are more reliable than others.

By and large, point-of-care tests are more accurate than home-based tests (due in part to home user error), while blood tests tend to be more accurate than saliva or urine tests (due to the higher concentrations of HIV in blood). Improper sample collection or storage can also undermine the accuracy of a test.

With that being said, clinics in the U.S. report a 98.5 percent accuracy when using an antibody test and a 99.9 percent accuracy when it is combined with a confirmatory test. This translates to one false-positive result for every 250,000 tests. Newer generation tests promise even better results.

By contrast, at-home tests are far less sensitive than point-of-care tests and may have as many as one false negative per every 12 tests.

Certain diseases can also trigger a false-positive test result, including syphilis, lupus, and Lyme disease. Confirmatory testing will almost always weed out these incorrect findings.

Risks and Contraindications

There are few risks associated with HIV testing. If a blood draw is required, you may experience soreness, swelling, and bruising at the injection site. Lightheadedness and infection are also possible.

If you are afraid of needles or squeamish about blood, advise the nurse or phlebotomist in advance. Others testing options may be available. Additionally, if you have hemophilia or are taking blood thinners, a child-sized butterfly needle may be used to reduce the risk of bleeding.

There are no contraindications for HIV testing.

Before the Test

The HIV test requires no preparation other than your readiness to take the test. With that being said, HIV remains a highly stigmatized disease, and people will often avoid HIV testing out of fear of disclosure.

If concerned about your privacy, find a clinic that offers either confidential testing (in which your name is shared only with your health provider, your insurance company, and a government reporting agency) or anonymous testing (where your name is shared with no one).

Timing

Timing is an important part of HIV testing. If you have been infected with HIV, there will be a period of time, called the window period, when the test cannot deliver an accurate result. 

Because HIV tests generally detect antibodies and/or antigens, you would need to wait until your body has produced enough of these to elicit a positive result. If you test too early, you will get a false-negative reading. Even with the NAT, you need would need to wait until the virus has replicated to detectable levels

The window period can vary by the test used and range from many as 55 days for an at-home test to as little as seven to 14 days for a NAT. Because detectable levels can also vary by individual, most clinics will advise you to wait no less than:

  • Three weeks before getting a NAT
  • One month before getting a combination HIV Ag/Ab test
  • Three months before getting any of the other tests

Location

HIV tests are available at many medical and public health facilities. These include hospitals, clinics, retail pharmacies, community-based HIV organizations, antenatal and family planning clinics, youth drop-in centers, mobile testing sites, and drug and alcohol treatment centers.

To find a testing site near you, use the online locator offered by the U.S. Department of Health and Human Services. Many of the sites offer walk-in testing. Others require an appointment.

Food and Drink

There are no food or drink restrictions for an HIV test. However, if you are using an at-home oral test, avoid brushing your teeth or using a 30 minutes beforehand as this may affect the results.

What to Bring

Even if you are undergoing anonymous testing, the facility may require government-issued ID to confirm your residency. Call in advance for details. You should also check to see if they accept your insurance. If so, bring your insurance card.

You may also want to consider bringing someone with you if you are unsure how you might react to a positive HIV diagnosis. Having support can be very important.

Cost and Health Insurance

The cost of an HIV test can range anywhere from $20 to $40 for a non-reactive (negative) test and $90 to $150 for a confirmed reactive (positive) test. Most insurance plans, including Medicare and Medicaid, will cover the cost in full as part of the Affordable Care Act’s essential health benefits.

By contrast, an at-home HIV test can cost between $25 and $50, while mail-in versions can range in price from $50 to $90. It is important to note that, while point-of-care tests are typically covered by insurance, at-home test kits may not be. Check with your insurance provider to understand which tests may or may not be covered.

If you are uninsured, you can find low- to no-cost testing sites through the GetTested locator offered by the Centers for Disease Control and Prevention.

Other Considerations

It is a mistake to think that there is nothing you can do if you’ve been recently exposed to HIV. If you have had sex without a condom, shared needles, or have some other form of high-risk exposure, you may able to avert the infection by starting HIV post-exposure prophylaxis (PEP) within 48 hours.

PEP involves a 28-day course of two or three antiretroviral drugs depending on the severity of your exposure. Used by healthcare workers and in cases of rape, the strategy may reduce your risk of infection by as much 79 percent.

During the Test

On the day of the test, after registering and confirming your insurance information, you may be asked to sign a consent form stating that you are aware of the purpose and risks of the procedure.

Many sites will also ask you fill out a questionnaire to get some background information on you, including your ethnicity, sexual orientation, sexual activity, and substance use, and whether you have had an HIV test before. Some of the information is for confidential reporting purposes; other are to used to assist with counseling.

The procedure itself involves three steps: pre-test counseling, the HIV test, and post-test counseling. Depending on the test being performed, the process can take 30 minutes to 45 minutes. Walk-in centers may take far longer.

Pre-Test

Pre-test counseling is a performed in private room with a qualified health professional. During the counseling, you may be asked about the recent exposure, if there was one, as well as your sexual or recreational drug practices. The questions are not meant to judged or embarrass you; rather, they help the counselor gain a better understanding of your personal risk of infection.

The counselor will then explain what HIV and AIDS are, how the test in performed, what a window period is, and what a positive and negative result mean. If it is determined that you are testing too soon, the counselor may request that you come back when the test is more likely to be accurate.

Feel free to ask any question you need. There is no such thing as a bad question.

Throughout the Test

The testing procedure in a clinic can vary based on whether you are taking a rapid HIV blood test, a rapid HIV oral test, or an HIV antibody blood test, or an HIV antibody saliva test. (The urine test, while approved, is rarely used in a clinical setting, in part because it is less accurate than any of the other tests.)

A rapid HIV blood test would be performed as follows:

  • Your finger would be cleaned with an antiseptic wipe.
  • Using a spring-loaded tool called a lancet, the health professional would prick your finger to draw a drop of blood.
  • The blood would be drawn into a tiny glass tube called a pipette.
  • The pipette would be placed in a reagent called a buffer.
  • The buffer and two other chemicals (a dying agent and clearing solution) would be poured into a plastic well called a membrane.
  • After 15 to 20 minutes, the membrane would be checked.
  • If the membrane has one dot on the bottom, the test is non-reactive (negative).
  • If the membrane has two dots, the test is reactive (preliminary positive). A confirmatory blood test would then be performed, the result of which would be received in a few days.

A rapid HIV oral test would be performed as follows:

  • An oral swab called a wand would be swiped between your teeth and upper and lower gum only once. The wand should be swiped no more than once.
  • The wand would be placed in a buffer solution for 20 minutes.
  • If the window in the handle has one line, the test is non-reactive (negative).
  • If the window has two lines, the test is reactive (preliminary positive). A confirmatory blood test would then be performed. If you used a home kit, you would call the toll-free number included in the kit to be connected the support helpline.

An HIV antibody blood test would be performed as follows:

  • An elastic band would be placed on your upper arm to make a vein swell.
  • The skin would be cleansed with antiseptic swab.
  • A wing-shaped device called a butterfly needle would be inserted the vein. The butterfly needle, which is attached to a narrow catheter, is less prone to jiggling as your blood is being drawn.
  • Between 1 to 4 milliliters (mL) of blood would be extracted into a vacuum-sealed test tube called a vacutainer.
  • The needle would then be removed and your arm bandaged.
  • The tube would be sent to a lab.
  • You would need to return for your test results in a week or two. If the sample is reactive (preliminary positive), the lab would immediately run a confirmatory test using the same blood sample.

An HIV ELISA saliva test would be performed as follows:

  • An oral swab called a wand would be placed between your cheek and gum for two to five minutes.
  • The wand would then be placed a buffer solution.
  • The wand handle would be snapped off.
  • The buffer solution would be sealed and sent to the lab.
  • You would need to return for your test results in a week or two. If the sample is reactive (preliminary positive), the lab would immediately run a confirmatory test using the same sample.

Interpreting the Results

Irrespective of your test results, post-test counseling would be performed. The aim of the counseling is two-fold: the help you understand what the results mean and to provide you the "what’s next" to keep you safe and healthy.  

The test results are interpreted as follows:

  • If the preliminary test is non-reactive, you would be HIV-negative, meaning that you have either not been infected or have tested too soon. While you would require no further testing, you would be advised on ways to reduce your future risk and whether routine testing is needed if you are at high risk of infection.
  • If the preliminary test is reactive, the result would be considered a preliminary positive. To confirm the result, the lab would use a more sophisticated test called the HIV differentiate assay and possibly the NAT. If the confirmatory tests are both non-reactive, you can be assured with a high level of confidence that you are HIV-negative.
  • If your preliminary and confirmatory tests are both reactive, you would be HIV-positive, meaning that you have been infected with HIV. Post-test counseling would be focused on both your emotional needs and medical needs.

Follow-Up

Upon receiving a HIV-positive diagnosis, you would be advised that there are treatment options and support systems to link you to medical care. You may also be referred to a care navigator who can assist you with referrals and any financial, emotional, family, legal, or drug treatment services you need.

If you feel overwhelmed, you can request to discuss these things on another day or use the time to ask as many questions as you need. Coming to terms with an HIV diagnosis is ultimately a process. Don’t feel rushed.

However, if you are ready to proceed and the test was performed in a clinic or hospital, you may be asked to undergo additional tests called a CD4 count and HIV viral load. The CD4 count measures the number of immune cells (called CD4 T-cells) in your blood and helps establish how strong your immune system is. The viral load uses a similar technology to the NAT and counts how many viruses there are in a microliter (µL) of blood.

Both the CD4 count and viral load help establish your baseline status before treatment and will be routinely retested to assess your response to therapy.

HIV treatment should ideally be started at the time of diagnosis. Genetic tests may be used to identify which drugs work best for you. The drug therapy itself typically involves a once-daily dose and, if taken as prescribed, can ensure a normal quality of life and a near-normal life expectancy.

A Word From Verywell

Receiving an HIV diagnosis can be a life-altering event, and there is often no way to know how you will react to the news. Whatever your response—whether it is to go silent, cry, and get angry—accept that this is normal. Some people might even feel a sense of relief from no longer having to wonder whether they "have it or not."

Whatever your response, it is important to remember that a positive diagnosis does not mean the same thing that it used to. Advances in HIV therapy are such that you can now live a long and healthy life and may never be faced with the prospect of a serious HIV-related illness or AIDS.

By knowing your HIV status, you can make an informed choice on how to protect others from infection and yourself from reinfection. Moreover, by taking your drugs as prescribed, you will be far less likely to infect your partner.

This to not suggest that living with HIV is without its challenges. If you are having trouble coping, consider joining an support group or seeking one-one-one counseling from a qualified therapist.

On the other hand, if you are experiencing extreme depression or anxiety, ask for a referral to a psychiatrist who may be able to offer medications and therapy to help you better cope.   

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