Establishment of qualitative human immunodeficiency virus type 1 nucleic acid amplification test as an adjunct confirmatory test in low-prevalence areas and small- and medium-sized diagnostic laboratories.

Two simple and inexpensive in-house qualitative human immunodeficiency virus type 1 nucleotide amplification tests (HIV-1 NATs) were established as adjunct confirmatory HIV test for HIV antigen (Ag)-positive specimens identified from HIV screening test and for patients with indeterminate or negative HIV antibody (Ab) confirmatory test results. The limit of detection was <1000 copies/mL, which is lower than that of the HIV Ag/Ab combination assay. One test using QL1 detected all 11 HIV-1 subtypes/circulating recombinant forms/group samples with almost equal analytical sensitivity, and the other test, using QL2, also detected all, except for two group O samples. In the examination of 28 HIV-1 Ag-positive samples using Determine HIV Early Detect, 27 samples were reactive and one HIV-1 Ag-pseudo-positive sample was non-reactive using both methods. These in-house qualitative HIV-1 NATs are useful for confirming HIV-1 Ag-positive cases and excluding HIV-1 Ag false-positive cases in areas with low HIV prevalence and small- and medium-sized diagnostic laboratories.