AIDS test kit

The microtitration plate wells are coated with HIV-1 and HIV-2 recombinant antigens. The sample is incubated in the wells. If sample contains antibodies against HIV-1 or HIV-2 they will bind to the antigens present in the wells. The unbound fraction is eliminated by washing. In the next step, is added the conjugate which contains the same antigens than the plate conjugated to peroxidase. They will bind to the antibodies if they were present in the sample. The unbound conjugate is removed by washing. Then, a solution containing tetramethylbenzidine (TMB) and hydrogen peroxide is added. The reactive samples develop a light blue color that changes to yellow when the reaction is stopped with sulfuric acid.