HIV Testing

Overview

CDC advises:

• At least one HIV test in a lifetime for all persons 15 years of age or older.
• HIV screening for persons with certain risk factors at least annually.
• Including HIV screening in the routine panel of prenatal tests during pregnancy.
• Repeating screening in the third trimester of pregnancy in jurisdictions with elevated rates of perinatal HIV infection.

Note: Sexually active gay and bisexual men may benefit from more frequent testing (every 3 to 6 months).

Being diagnosed with HIV early and starting treatment right away can lead to better health outcomes for people with HIV and reduce the chances of transmission.

People who test negative for HIV can make decisions about sex, drug use, and health care that can help prevent acquiring HIV. Taking HIV medicine called pre-exposure prophylaxis (PrEP) is highly effective for preventing HIV infection.

Types of HIV tests

HIV tests are very accurate, but no test can detect the virus immediately after infection. How soon a test can detect HIV depends on the window period for the type of test and on the presence of antiretroviral medications used for PrEP at time of infection. Antiretroviral medications can delay the ability of a test to detect HIV infection.

There are three types of HIV tests that are FDA approved to aid in the diagnosis of HIV infection or as a supplemental test to confirm HIV infection:

Antibody tests

• Look for antibodies to HIV in a person's blood or oral fluid. Antibodies are produced by a person's immune system after exposure to viruses like HIV.
• Most often used as HIV point-of-care tests and the one FDA-approved HIV self-test.
• Sometimes use blood from a vein rather than a finger stick or oral fluid that, in general, can detect HIV sooner after infection.

Window period: An antibody test can usually detect HIV infection 23 to 90 days after exposure in the absence of antiretroviral medications.

Antigen/antibody tests

• Look for both HIV antigens and antibodies. Antigens are parts of the virus that cause a person's immune system to activate.
• Can detect an antigen called p24 if a person has HIV, which is produced before antibodies develop.
• Are recommended for testing done in labs and are commonly done in the United States.

Window period: An antigen/antibody test performed by a lab on blood from a vein can usually detect HIV infection 18 to 45 days after exposure. Antigen/antibody tests done with blood from a finger stick can usually detect HIV infection 18 to 90 days after exposure in the absence of antiretroviral medications.

Nucleic Acid Tests (NATs)

• Look for the actual virus in the blood.
• Considered for use for people who have had a recent possible exposure, and their screening test was non-reactive.

Window period: A NAT can usually detect HIV 10 to 33 days after exposure in the absence of antiretroviral medications.

Confirming test results

An initial HIV test will usually be either an antigen/antibody test or an antibody test. If the initial HIV test is a point-of-care or self-test and it is positive, the person should go to a health care provider for follow-up testing. If the initial HIV test is a lab test and it is positive, the lab will usually conduct follow-up testing on the same blood sample as the initial test.

Although HIV tests are generally accurate, follow-up tests allow the health care provider to confirm the result.

Highlights

Importance of HIV testing for treatment and prevention of HIV infection

People with HIV who know their status can get HIV treatment (called antiretroviral therapy or ART) and remain healthy for many years. Studies show that the sooner people start HIV treatment after diagnosis, the more they benefit.

HIV treatment reduces the amount of HIV in the blood (called viral load), reduces HIV-related illness, and prevents transmission to others. People with HIV who take HIV treatment as prescribed and get and keep an undetectable viral load (or stay virally suppressed) will not transmit HIV to their sex partners.

People who test negative for HIV can make decisions about sex, drug use, and health care that can help prevent acquiring HIV. Taking HIV medicine called pre-exposure prophylaxis (PrEP) is highly effective for preventing HIV infection.

Test classifications

Laboratory tests

Laboratory tests are usually performed on blood samples and can detect HIV antibodies, HIV antigen/antibodies, or HIV nucleic acid (RNA). Lab-based testing allows for the earliest possible detection of newly acquired HIV and is preferred for PrEP initiation and continuation.

Point-of-care tests

Point-of-care tests, also referred to as CLIA-waived rapid tests, can be done in a variety of clinical and community-based settings, such as outpatient sexual health clinics, jails, mobile health units, schools, or in a person's home. Point-of-care tests are performed by trained personnel, and most take less than 25 minutes to yield results.

Self-tests

HIV self-tests are rapid tests that allow people to find out their result in their own home or other private location. The person collects their own sample, follows the instructions, and obtains a result in less than 30 minutes. The availability of HIV self-tests in the US may help increase awareness of HIV infection for people who wouldn't otherwise get tested for HIV. There is currently only one FDA-approved self-test in the United States.

While HIV self-tests are available for retail purchase, CDC encourages health departments to consider providing HIV self-tests as an additional strategy to increase testing among populations most affected by HIV. Findings from HIV self-testing research and the additional resources listed below may be helpful if you are considering offering HIV self-testing in your program.

Oral fluid self-tests should not be used for PrEP initiation or maintenance due to their lower sensitivity in detecting recent HIV infection, unless no other testing options are available.

HIV testing before PrEP initiation

A negative HIV test should be documented within the week before starting PrEP, ideally with laboratory-based testing. A rapid, point-of-care, fingerstick antigen/antibody blood test is an option for same-day PrEP initiation. When PrEP is prescribed based on a negative point-of-care test, results should be confirmed with a lab-based HIV test. Same-day PrEP initiation is not appropriate for patients with possible acute HIV infection.

HIV testing should be conducted at a frequency based on the PrEP medication given. CDC has developed guidance for providing PrEP when facility-based services and in-person patient-clinician contact is limited.

Reaching more people with HIV self-tests

Some persons who have behaviors that increase the chances of getting HIV do not always readily engage in routine health care. Reaching them via the internet or social media provides an opportunity for implementing HIV self-testing programs. HIV program planners should consider mailing out HIV self-tests to internet-recruited persons as an additional component of their HIV prevention portfolio.

Testing in nonclinical settings

HIV testing can be done in a variety of nonclinical or community-based settings, as well as outreach sites, or in a person's home. Nonclinical settings typically provide same-day point-of-care HIV testing and might offer other HIV prevention services. Testing in nonclinical settings may also include outreach and recruitment to disproportionately affected populations.

Offering HIV testing in these settings is an effective way to bring HIV testing to people who might not otherwise get tested.

CDC guidance on HIV testing in nonclinical settings

CDC issued program guidance for HIV testing providers called Implementing HIV Testing in Nonclinical Settings: A Guide for HIV Testing Providers. This guide supports the implementation of HIV testing services in nonclinical settings in the United States.

The purpose of the guide is to familiarize providers with issues that impact delivery of HIV testing services in nonclinical settings. Although this guidance is intended for CDC-funded nonclinical HIV testing providers, any nonclinical HIV testing provider may also find the content useful.

Related recommendations and guidelines

Clinical Laboratory Improvement Amendments (CLIA) Certificate of Waiver

The Clinical Laboratory Improvement Amendments of 1988 (CLIA) established quality standards for laboratory testing to ensure the accuracy, reliability, and timeliness of patient test results. CLIA requires that any facility examining human specimens for diagnosis, prevention, or treatment of a disease, or for assessment of health must register with the Centers for Medicare & Medicaid Services (CMS) and obtain CLIA certification.

Laboratory certificate requirements for HIV testing in nonclinical settings

Nonclinical HIV testing sites using point-of-care HIV tests must either obtain their own Certificate of Waiver under CLIA or establish an agreement to work under the CLIA certificate of an existing laboratory. Agencies should contact their state or local health department for more information, including how to apply for a CLIA waiver.

More information about CLIA certification and CLIA-waived tests, including how to establish a CLIA-waived HIV testing site, can be found on the CDC CLIA home page, or from your state CLIA office.

CLIA-waived rapid HIV tests

The Food and Drug Administration (FDA) has approved several CLIA-waived rapid HIV tests, also known as point-of-care tests, which must use unprocessed specimens like whole blood or oral fluid, be easy to administer, and carry minimal risk of incorrect results. More than 1,400 test systems have received waivers, and a Certificate of Waiver is required if an agency intends to conduct only point-of-care HIV testing.

These tests can be used at both clinical and nonclinical sites, such as community and outreach settings. Any agency conducting these tests is considered a clinical laboratory, and nonclinical sites must either apply for their own CLIA Certificate of Waiver or work under an existing laboratory's certificate. Additionally, facilities performing these tests must have a quality assurance plan to ensure accurate testing and correct any mistakes. Sites ordering the tests must certify compliance with FDA requirements, which include:

• Sales that are restricted to clinical laboratories.
• A quality assurance plan for point-of-care HIV testing must be in place.
• Staff that have been trained to perform the test using manufacturer's instructions.
• Providing to clients a "Subject Information" pamphlet before the test is given and appropriate information when results are provided.

State regulations

Many states have additional regulations that apply to laboratory testing, and some require separate applications to the state agency. Some regulations also apply specifically to HIV testing. These regulations may require training to provide testing services and care.

Before applying, you should consider these requirements and the best method for receiving testing authority, including contacting your state health department and your local CMS inspector for guidance. View CLIA contacts for all states.

Exceptions: Washington State is exempt from CLIA regulations. New York is also exempt from CLIA, except for physicians' office labs, which are required to have a CLIA certificate. Both states have their own requirements that meet or exceed CLIA requirements.

How to apply for a CLIA Certificate of Waiver

Obtaining a Certificate of Waiver is generally a straightforward process. An application (form CMS-116) is available at the CMS website or from your state health department. Check out the Laboratory Quick Start Guide for what information you need to apply.

The Certificate of Waiver application should be forwarded to the address of the local state agency of the state in which the testing will be performed. You can also contact your local state agency for assistance in filling out the application.

The Certificate of Waiver is valid for two years. A renewal application will need to be completed and sent to the state agency not less than 9 months before the certificate's expiration date.

For additional information or assistance in filling out the CLIA waiver application call CMS toll-free: 877-267-2323; Local: 410-786-3000; TTY Toll-Free: 866-226-1819; or visit the CLIA website.

FDA-approved HIV tests

Resources

OraQuick HIV Self-Test

OraSure Technologies provides customer support and detailed information about their HIV self-test product, OraQuick HIV Self-Test. Visit https://oraquick.com for more information.

How to start an HIV self-testing program

The New York City Department of Health provides information on their self-testing programs and considerations for other health departments that want to set up similar programs. Learn more about the Home HIV Test Giveaway. Visit https://www.health.ny.gov/press/releases/2023/2023-06-27-hiv_self_test.htm for more information.

Testing Beyond the Clinic webinar series

The Testing Beyond the Clinic webinar series is designed to provide ongoing information about nonclinical, self-collected HIV and STD testing logistics and program implementation. Presented by the National Coalition of STD Directors. Visit https://www.naccho.org/blog/articles/on-demand-webinar-series-testing-outside-the-clinic for more information.