The Facts About Rapid HIV Tests

Comparison of Currently Available Rapid Assays

Courtesy OraSure Technologies

The U.S. Preventive Services Task Force currently recommends the once-off HIV testing of all Americans ages 15-65 as part of a regular doctor visit. Additionally, individuals at high risk of HIV (e.g., injecting drug users, men who have sex with men) are advised to be tested annually.

One of the more popular means of HIV detection are rapid tests, available as both point-of-care and in-home versions. They allow patients to get results in as little as 20 minutes, reducing the anxieties which can sometimes prevent people from returning for their results.

Using technology similar to traditional antibody tests, rapid HIV tests are available and either test blood (requiring your doctor to prick your finger) or saliva (requiring a mouth swab).

There are a number of rapid HIV tests currently approved for use by the U.S. Food and Drug Administration (FDA). Some are only available at your doctor's office while one specifically (the OraQuick In-Home HIV kit) can be purchase online or at your local pharmacy. 

Among the most widely available point-of-care tests are:

OraQuick Advanced Rapid HIV-1/2 Antibody Test

This rapid test has been approved for use with venous blood, plasma and oral fluids for the detection of HIV-1 and HIV-2. The test consists of a small test paddle. The test area on the paddle is impregnated with HIV-1 and HIV-2 proteins. The test specimen (blood, plasma, or oral fluid) is applied to the paddle (in the case of oral fluid the paddle is swabbed in the inside of the mouth) and placed in developer solution.

If the specimen contains HIV, it binds with the impregnated proteins on the HIV testing paddle causing in a red line to appear. Red lines appearing in the test area and control area of the paddle indicates a positive test. All positive tests require a confirmatory blood test. The rapid test should be read no sooner than 20 minutes and no later than 40 minutes after the sample is placed in the developing solution.

Reveal G2 HIV-1 Antibody Test

This type of rapid HIV test has been approved for use with plasma or serum specimens. While the test only takes 3 minutes to develop, the test is more complex than the OraQuick because it requires centrifuged serum or plasma. The test consists of a cartridge with a test area. Like the OraQuick, any HIV present in the test specimen binds with the protein impregnated in the test area, causing a red dot to appear. If a red dot appears along with a red line used as a control the test is considered positive, requiring a confirmatory test.

Uni-Gold Reconbigent HIV-1 Test

The Uni-Gold has been approved for us with whole blood, plasma, or serum from a venipuncture or finger stick. It consists of a rectangular cartridge with a test area, a control area, and a specimen well. The specimen is applied into the specimen well and allowed to absorb, tracking along the test strip past the control and test areas. As is true in the first two tests we've discussed, any HIV in the specimen binds to the proteins in the test area, causing a red line to appear.

A test is considered positive if a red line appears in both the test area and the control area. A sample is considered adequate if the specimen well is red in color. Like all rapid tests if the test is positive a confirmatory test is required.

Multispot HIV-1/HIV-2 Rapid Test

This HIV test has been approved for use on frozen and fresh plasma, whole blood, or serum. Multispot consists of a test cartridge and five reagents: The cartridge contains a membrane on which microparticles have been immobilized in four spots; two HIV-1 test spots; one HIV-2 test spot; and one control spot to verify that the specimen is adequate.

The test is considered positive for HIV-1 if the control spot and either or both of the HIV-1 spots turn purple, and positive for HIV-2 if the control and HIV-2 spots appear. If purple appears in the control spot, the HIV-2 spot, and one or both of the HIV-1 spots, the test is considered HIV reactive (undifferentiated). In this case, the specimen may be tested by additional methods which allow differentiation between HIV-1 and HIV-2. The test is negative when only the control spot appears. The absence of the control spot indicates an invalid result, regardless of any other spot pattern.

False Negative Tests Do Occur

One problem with rapid HIV testing is the occurrence of false positive and negative tests. While newer generation versions have improved upon false positive results, there remains some concern about the in-home version of the OraQuick rapid test I ( pictured). 

According to the results of Phase III human trial, as many as one out of 12 OraQuick in-home tests returned a false negative result, due in part to the lower sensitivity of the product. The tests can also miss infection if performed during the so-called window period, where the level of antibodies is too low to be accurately detected. User misuse is also cited as a potential concern.

Despite this, advocate groups contend that tests like this put the control back into the individual's hands, providing a greater sense of autonomy and confidentiality.

As a result, labs in the U.S. are turning more toward the use of combination antigen/antibody tests (including the Alere Determine HIV-1/2 Combo) which not only significantly shortens the window period but, in some cases, increases the likelihood of a correct response during the very early (acute) stage of infection.

View Article Sources
  • Pant Pai, N.; Balram, B.; Shivkumar, S.; et al. "Head-to-head comparison of accuracy of a rapid point-of-care HIV test with oral versus whole-blood specimens: a systematic review and meta-analysis." The Lancet Infectious Diseases.January 24, 2012; 12(5):373-380.
  • Pilcher, C.; Louie, B.; Facente, S.; et al. "Performance of Rapid Point-of-Care and Laboratory Tests for Acute and Established HIV Infection in San Francisco." PLOS | One. December 12, 2013; DOI: 10.1371/journal.pone.0080629.
  • U.S. Food and Drug Administration (FDA). "First Rapid Home-Use HIV Kit Approved for Self-Testing." FDA Consumer Health Information. Silver Spring, MD; July 2012. Document: UCM311690