HIV Rapid Testing Kits

Rapid HIV testing kits provide clinicians with a means by which to get a quick answer to the question of whether an individual is infected with the human Immunovirus. HIV is a serious infection with lifelong consequences, and so having a method of testing which can determine whether or not a patient is infected within half an hour as opposed to the several weeks of classic tests is amazingly useful.

For any testing kit to make its way into widespread medical and even commercial usage, a number of important points need to be considered by authorities like NICE (National Institute for Health and Clinical Excellence) and the FDA (Federal Drug Authority). The FDA is an American organization which approves the manufacture and clinical use of drugs and testing equipment, and FDA approval is needed for tests like these to enter widespread usage. What FDA approval means to patients and consumers is that a drug has been tested vigorously for safety and effectiveness, and in terms of HIV rapid tests it means that a particular testing kit has been investigated for its reliability and accuracy.

In this article we look at some of the FDA approved rapid testing kits in use and how they work.

The OraQuick Test

 The OraQuick test is also referred to as the OraQuick Advanced Rapid HIV-1/2 Antibody Test, and as the name suggests it is a quick, oral method of detecting both strains of the HIV virus (1 and 2) by means of antibody detection.

While originally an oral test, OraQuick has actually been approved for blood and plasma testing as well. The testing kit is very simple and looks like a paddle with a specific test area loaded with HIV strain 1 and strain 2 molecules. The testing fluid, be it blood or saliva, is placed on the specified test area on this paddle, and is then immersed in a specially formulated solution for a minimum of 20 minutes and a maximum of 40 minutes.

If the test fluid contains any HIV-1 or HIV-2, the virus will bind to the molecules in the testing area resulting in the appearance of a red line which indicates a positive result. While OraQuick is very reliable, all positive results need to be confirmed through a blood test to eliminate the possibility of a false positive (where a test inaccurately reports the presence of HIV).

The Uni-Gold Recombigen HIV-1 Test

The Uni-Gold test is designed to detect one particular subtype or strain of the HIV virus which is simply referred to as HIV-1. This is the more common form of the virus, and this particular testing kit has been FDA approved for blood testing through either the puncture of a vein or through ‘finger sticking’. Finger sticks were first incorporated into testing kits for diabetes, and are basically a fine sharp point incorporated into testing equipment which causes a minute puncture in your finger, just large enough to get a drop or two of blood (the volume needed for the test in any case).

This testing kit is different in terms of its design when compared to the OraQuick test. The Uni-Gold product is a small rectangular structure with a specimen well (into which you insert your blood sample) and a testing and control area. The specimen is drawn across from the well into the control and test areas, both of which contain HIV proteins (as in the OraQuick testing kit). If the virus is present it binds to these proteins and forms a clear red line. For a positive test both the control and test areas need to indicate a red line, and as with any other rapid test a confirmatory blood test is needed as well.

The Reveal G2 HIV-1 Antibody Test

The Reveal Test is distinct from the two rapid testing methods already mentioned in this test in that it is only approved for the testing of either serum or plasma. Serum and plasma are both derivatives of blood, however this indication means that simply testing your blood won’t give you an accurate result. Fortunately serum and plasma are usually easily extracted from a blood sample, and once that has been done the Reveal Test takes as little as 3 minutes to yield a result.  

Like the Uni-Gold test, Reveal is a cartridge with a distinct test area. The plasma or serum sample is placed into the cartridge and, as in the previous two tests described, proteins bind the HIV virus to yield a visible red line. Again a positive result requires re-testing to confirm.

The Multispot HIV-1/HIV-2 Rapid Test

Finally the Multispot test is designed for both HIV-1 and HIV-2 detection, and has been FDA approved for use on either fresh or frozen blood or its derivatives, plasma and serum. The Multispot test is slightly more complex in that it is actually made up of a test cartridge and some test solutions that need to be used in a particular way.

These testing solutions, also referred to as test-reagents are as follows: A solution in which the test fluid is diluted, a wash solution, a conjugate (a substance which binds to the HIV virus), a developing reagent (which makes the test result clearly visible), and a stop solution (which effectively stops all the chemical reactions which take a sample and translate it into a positive or negative result).

The cartridge itself is also more complex, featuring a two HIV-1 and one HIV-2 test areas, as well as a control area which is used to check whether the blood, serum, or plasma sample can be accurately tested. For a positive test for HIV-1, both the control spot and either one or both HIV-1 testing spots must turn purple, and for a positive test for HIV-2, both the control and test spot also need to change color. If all the test spots change color then further testing is needed to determine whether HIV-1 or HIV-2 is present. If only a control spot forms then the test is negative, and if there is no color change in the control area the test is invalid.

This testing kit is much more complex than its main competitor, the OraQuick test, but it is noted for its reliability. Each of these test kits has its own particular uses in the clinical setting, and new tests are constantly emerging and improving.

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