HIV-2 EIA

Additional testing using an FDA-licensed EIA for antibodies to HIV-2 is performed on all samples with indeterminate or negative HIV-1 Western blot results. Valid results are:

REACTIVE - The presence of antibodies to HIV-2 antigens is suspected. However, because of extensive cross-reactivity between HIV-1 antibodies and HIV-2 antigens, a conclusive determination of HIV-2 reactivity can not be made. Additional supplemental tests may be required.

NON-REACTIVE - Antibodies to HIV-2 are absent from the sample.

Samples REACTIVE on HIV-2 EIA may be subjected to an investigational HIV-2 Western blot assay. Valid test results for this assay are:

NEGATIVE - The sample does not contain detectable antibodies to HIV-2

INDETERMINATE - Any pattern of reactivity which does not produce a negative or positive result.

POSITIVE - Antibodies to p26 (gag) and gp34 (env transmembrane), or gp105 (gp34 trimer) are present in the sample.

The final interpretation using the FDA's confirmatory algorithm is described in TABLE A-4.