THE RAPID 1-2-3® HEMA CASSETTE HIV TEST
The RAPID 1-2-3® HEMA CASSETTE HIV ½ TEST (the TEST) is an in vitro, rapid, qualitative two site sandwich immunoassay used for the detection of antibodies to HIV 1/2 virus in human serum, plasma and in freshly-collected human whole blood.
Acquired immunodeficiency syndrome (AIDS) and AIDS related complex (ARC) are clinical conditions initiated by HIV ½ viral infection. Part of the body’s attempt to deal with this infection is the production of antibodies against the viruses. These antibodies are typically directed against conserved parts of the virus (unchanging antigens). When the antibodies have reached or exceeded a certain concentration in blood, their presence can be detected visually by the test.
PRINCIPLES OF THE TEST
The test utilizes the principle of immunochromatography, a unique two site immunoassay on a membrane for the qualitative detection of antibodies recognizing HIV ½ antigens in human whole blood, serum or plasma. A mixture of highly purified recombinant antigen of gp 41, recombinant p24 combined to subtype O specific synthetic peptide, representing HIV-1 and recombinant gp36 representing HIV-2 are coated on the membrane in the test region and anti-rabbit antiserum in the control region.
During the procedure, whole blood from a fingerstick (or an equal amount of serum/plasma), is collected into the pipette and is added onto the test cassette. Then, 5 drops of Diluent Solution is added. The Diluent/blood sample combination flows through the test strip within the test device. The fluid containing the combined sample will migrate up the strip by capillary action and hydrate a colored conjugate. IgG antibodies in this Sample/Buffer Solution bind to the conjugate and continue migrating up the strip and onto a membrane. If any of the antibodies bonding to the colored conjugate recognize viral antigen deposited in the form of a line at the test area of the membrane, a pink-purple line will be produced. Some antibody-conjugate complexes will migrate further up the membrane and bind to a line of reagent that recognizes IgG nonspecifically at the Control area of the membrane. The presence of any IgG antibodies should thereby produce a pink-purple line at the Control area and demonstrate that the test system has performed properly.
The presence of two pink-purple lines, one at the Test area and the other at the Control area, indicate a reactive or positive result. Whereas, the absence of the pink-purple line in the Test area indicates a non-reactive or negative result. The absence of a pink-purple line in the Control area, regardless of the presence or absence of a pink-purple line in the Test region signifies an invalid test. Any invalid test should be repeated.