RESUMEN
BACKGROUND: A new nucleic acid-based assay (simple amplification-based assay [SAMBA]) for rapid visual detection of human immunodeficiency virus-type 1 (HIV-1) by dipstick is described. The assay was designed to be simple, stable, robust, self-contained, and capable of detecting a broad spectrum of HIV-1 subtypes and recombinant forms. METHODS: The performance of the SAMBA HIV-1 test (amplification and detection chemistry) was evaluated using the World Health Organization HIV-1 RNA Genotype Reference Panel, with clinical samples representing various viral subtypes and recombinant forms common in sub-Saharan Africa. Sixty-nine randomly selected and blinded clinical samples that had undergone HIV-1 genotypic resistance analyses in a large London teaching hospital were also tested. These samples included 14 different viral subtypes or recombinant forms with viral loads of 78-9.5 x 10(6) copies/mL. RESULTS: The sensitivity and viral subtype coverage of the SAMBA HIV-1 test were either comparable to or better than those of the commercially available nucleic acid-based HIV-1 diagnostic tests. CONCLUSIONS: The unique characteristics and competitive performance of the SAMBA HIV-1 test render it suitable for point-of-care and near-patient testing in both developed and developing countries.
Asunto(s)
Infecciones por VIH/diagnóstico , Técnicas de Diagnóstico Molecular/métodos , Técnicas de Amplificación de Ácido Nucleico/métodos , Sistemas de Atención de Punto , África del Sur del Sahara , Humanos , Sensibilidad y EspecificidadRESUMEN
First-void urine (FVU) is the preferred specimen for the diagnosis of urogenital Chlamydia trachomatis infection in men. We have developed FirstBurst, a urine collection device that collects the first 4 to 5 ml of FVU and yields a specimen with a sixfold higher C. trachomatis organism load than the regular urine cup by quantitative PCR (32,533 versus 5,271 plasmids/ml; P < 0.0001). Consequently, the use of FirstBurst to collect a urine sample improved the sensitivity of a rapid test for Chlamydia over testing of samples collected with a urine cup (82 versus 47% sensitivity using PCR as a reference; P < 0.0015).
Asunto(s)
Infecciones por Chlamydia/diagnóstico , Chlamydia trachomatis/aislamiento & purificación , Manejo de Especímenes/instrumentación , Manejo de Especímenes/métodos , Orina/microbiología , Adolescente , Adulto , Infecciones por Chlamydia/microbiología , Chlamydia trachomatis/genética , Humanos , Masculino , Reacción en Cadena de la Polimerasa/métodos , Sensibilidad y EspecificidadRESUMEN
The SAMBA HIV-1 Qual Whole Blood Test is a nucleic acid-based amplification assay for the qualitative detection of HIV-1 in whole blood of adults or infants. The test can be run on either the semi-automated SAMBA I system for clinical use or the fully automated, including readout, SAMBA II system for point-of-care use in resource-limited settings. We have assessed the performance characteristics of the SAMBA HIV-1 Qual Whole Blood Test on SAMBA I and SAMBA II. The limit of detection obtained for the two tests were 518IU/ml and 399copies/ml on SAMBA I and 457IU/ml and 433copies/ml on SAMBA II. Test specificity on both systems was 100% with a panel of 503 HIV-1 negative samples. Evaluation of test reproducibility showed 100% concordance with expected gold standard results as well as 100% agreement between operators, days, and runs as well as within runs on both SAMBA I and SAMBA II. Our results thus show that the SAMBA HIV-1 Qual Whole Blood Test performs equivalently on SAMBA I and SAMBA II, and also suggest that the test is suitable for implementation in medium-throughput clinical facilities (SAMBA I) or low-throughput point-of-care (POC) settings (SAMBA II) in resource-poor regions.