False-positive result of a confirmatory human immunodeficiency virus line immuno assay in an apparently healthy individual--a case report.

A case of a false-positive result of human immunodeficiency virus (HIV) confirmatory immunoblot-based assay is described. Repeatedly borderline reactive anti-HIV screening enzyme immunoassay result obtained in a local hospital resulted in directing the sample to the Slovenian HIV/AIDS Reference Laboratory. In the Reference Laboratory, both anti-HIV screening assays and confirmatory Western blot were negative, while a confirmatory test INNO-LIA HIV I/II Score (Innogenetics, Ghent, Belgium) was anti-HIV-1 positive due to sgp120 and gp41 reactivity. The results of serological testing of the second sample obtained three weeks later were completely identical, while in the third sample obtained 5 months later, seroreversion was observed. Due to a negative dynamics in anti-HIV serological profile and repeatedly negative results of the molecular tests for HIV-1 and HIV-2, HIV infection was excluded and the results of test INNO-LIA HIV I/II Score were finally interpreted as false positive.