Análisis retrospectivo del rendimiento de Amplicor-PCR® para la detección de Mycobacterium tuberculosis en muestras respiratorias y no respiratorias con baciloscopia negativa: A retrospective analysis

Abstract

Commercial polymerase chain reaction (PCR) kits are widely accepted for analysis of smear positive respiratory specimens, but the sensitivity is variable for smear negative ones.To assess the PCR method usefulness in smear negative respiratory and non respiratory specimens.We compared the PCR results (AMPLICOR MTB test, Roche) of 235 specimens subjected to culture in Loewenstein-Jensen agar (as the gold standard).181 (76%) were respiratory and 54 (24%) extra-respiratory specimens. The sensitivity was 88%) and 50%>, respectively, specificity and PPV was 100%> in both cases. NPV was 99.4%> in respiratory specimens and 96.1% in non-respiratory specimens.The good performance of this PCR in smear negative respiratory specimens allows the clinician to take decisions based on the result of this exam. In extra-respiratory specimens the contribution is important only when the PCR result is positive.