Evelyn Stelzl, Rita Baumert, Josef Haas, Egon Marth, Harald H. Kessler
Evaluation of automated sample preparation for quantitative detection of human immunodeficiency virus type 1 RNA/Evaluierung einer automatisierten Probenvorbereitung zum quantitativen Nachweis von HIV-1 RNA
The COBAS AMPLIPREP instrument for automated sample preparation has recently been introduced. The COBAS AMPLIPREP/COBAS AMPLICOR HIV-1 MONITOR Ultrasensitive test, version 1.5, which includes this new molecular device, was evaluated and compared to the COBAS AMPLICOR HIV-1 MONITOR test, version 1.5, which includes a manual extraction protocol. Accuracy, linearity, interassay variation, and intra-assay variation were determined and a total of 126 clinical specimens were investigated. When the accuracy of the COBAS AMPLIPREP/COBAS AMPLICOR HIV-1 MONITOR test was examined, all but one result were found within ± 0.5 logs of the expected results. Furthermore, one of two samples containing 1.0 × 102 HIV-1 RNA copies ml–1 could not be detected. The determination of linearity resulted in a quasi-linear curve over at least 3 logs. For the determination of interassay variation, coefficients of variation were found between 15 and 43% for the COBAS AMPLIPREP/COBAS AMPLICOR HIV-1 MONITOR test and between 14 and 39% for the COBAS AMPLICOR HIV-1 MONITOR test. For the determination of intra-assay variation, coefficients of variation were found between 11 and 30% for the COBAS AMPLIPREP/COBAS AMPLICOR HIV-1 MONITOR test and between 13 and 30% for the COBAS AMPLICOR HIV-1 MONITOR test. When 126 clinical samples were tested with the COBAS AMPLIPREP/COBAS AMPLICOR HIV-1 MONITOR test and compared with the COBAS AMPLICOR HIV-1 MONITOR test, 93% of all samples yielded comparable results. Nine samples containing HIV-1 RNA concentrations close to the detection limit of the assays produced discrepant results. The new assay, which included the automated sample preparation, proved to be suitable for the routine molecular laboratory. It was found to be labor-saving and easy to handle.
LaboratoriumsMedizin, Walter de Gruyter
Print ISSN: 0025-8466
Volume: 28, 08/2004
Pages: 354 - 360
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