Evaluation of two indigenous rapid and two ELISA assays for the diagnosis of HIV infection India.

Purpose: Human immunodeficiency virus (HIV) diagnostic tests are being used extensively in India. However, the evaluation data on these assays are very limited. The present study evaluates indigenous HIV test kits manufactured in India. Materials and Methods: A total of 200 characterised specimens were assayed with Comb AIDS - RS Advantage HIV 1+2 Immunodot Test, Enzaids HIV 1+2 ELISA test, Enzaids Duet HIV Antigen+antibody ELISA test and Signal HIV Flow Through HIV 1+2 test kits. Performance characteristics of these assays were calculated. Results: Sensitivity, specificity, positive predictive value, negative predictive value and efficiency of all the assays were 100% except for Signal HIV Flow Through HIV 1+2 test kit. The specificity, positive predictive value and efficiency of the Signal HIV Flow Through HIV 1+2 test kit were 98.9%, 98.9% and 99.4%, respectively. The Enzaids Duet HIV kit was found to be extremely sensitive in detecting p24 Ag with the sensitivity of 1.5 pg/mL. Conclusions: To conclude, selection of better diagnostic assay is very much important to resolve discrepancies in HIV diagnosis. All these assays under evaluation in this report have got excellent performance characteristics and much suitable to use in serial testing algorithms in use for resources limited settings.

Replacement of HIV p24 Ag test by a multiplex RT-PCR method for primary screening of blood donors

Nucleic Acid Testing (NAT) as a tool for primary screening of blood donors became a reality in the end of the 1990 decade. We report here the development of an "in-house" RT-PCR method that allows the simultaneous (multiplex) detection of HCV and HIV-RNA in addition to an artificial RNA employed as an external control. This method detects all HIV group M subtypes, plus group N and O, with a detection threshold of 500 IU/mL. After validation, the method replaced p24 Ag testing, in use for blood donation screening since 1996 at our services. From July 2001 to February 2006, 102,469 donations were tested and 41 (0.04 percent) were found HIV-RNA reactive. One NAT-only reactive donation (antibody non-reactive) was observed, with subsequent seroconversion of the implied donor, giving a yield of 1:102,469. This rate is in contrast to the international experience that reports a detection of approximately 1:600,000 - 1:3,100,000 of isolated HIV-RNA donations.

O uso de testes de ácidos nucleicos (NAT) na rotina de triagem de doadores de sangue tornou-se uma realidade ao final da década de 1990. Descreve-se aqui uma metodologia de RT-PCR multiplex "in-house" que permite a detecção simultânea dos RNAs dos vírus HIV e HCV além de uma molécula artificial de RNA usada como controle externo. O método detecta todos os subtipos de HIV do grupo M e também do grupo N e O, com uma sensibilidade de 500 UI/mL. Após validação, este teste substituiu o do antígeno p24, até então na rotina de triagem em nosso laboratório, desde 1996. De julho de 2001 a fevereiro de 2006 foram testadas 102.469 doações e 41 (0.04 por cento) foram NAT reativas. Uma doação NAT isoladamente reativa (anticorpo não-reativa) foi detectada com soroconversão subseqüente do doador, portanto, o rendimento do NAT nesta população até o presente momento é de 1:102.469. Este número contrasta com a experiência obtida internacionalmente, onde taxas de 1:600.000 - 1:3.100.000 foram descritas.

Evaluation of a simultaneous HIV antigen and antibody detection test in Korean population

Current diagnosis of human immunodeficiency virus (HIV) infection relies on the detection of anti-HIV antibodies by enzyme-linked immunosorbent assay (ELISA). Recently, kits detecting both p24 antigenemia and anti-HIV/anti-HIV2 antibodies have been developed. Thus, it is necessary to compare those kits developed as such. The aim of this study was to evaluate the diagnostic efficiency of a simultaneous detection test of p24 antigen and anti-HIV1/2 antibodies in a low prevalence area. Eight hundred and four randomly selected sera proven negative for HIV infection and 110 sera from 54 patients diagnosed as HIV infected, obtained between 1999 and 2000, were used for this study. One commercial lot of panels composed of consecutive sera obtained from known HIV-infected patient was included. Anti-HIV1/2 antibodies were detected by two different commercial ELISA kits, one from Korean and the other from German manufacturer. P24 antigen test was performed by ELISA. The simultaneous HIV antigen and antibody detection test was carried out. In the meantime, HIV RNA PCR and anti-HIV and anti-HIV2 western blot assays were also performed to confirm the test results in cases the test results didn't agree. The simultaneous detection kit showed 100% sensitivity and 99.6% specificity. Furthermore, the test displayed the possibility of earlier diagnosis than conventional anti-HIV1/2 ELISA with the results obtained from a group of consecutive panel sera infected with HIV. From these results, we concluded that the simultaneous HIV antigen and antibody detection test can be applied as a substitute clinical screening test in the place of conventional anti-HIV1/2 ELISA, and there is the probable benefit of early diagnosis.