In-house PCR with DNA extracted directly from positive slides to confirm or exclude the diagnosis of tuberculosis: focus on biosafety.

The possibility to obtain DNA from smears is a valuable alternative to remedy the lack of samples when they are totally used for bacilloscopy; this technique solves the biosafety problem related to a possible accident with the transportation of flasks containing potentially transmissible clinical samples. Hence, the purpose of this study was to utilize the insertion sequence IS6110 for amplification of DNA from a smear-positive sample for tuberculosis (TB) diagnosis. Among the 52 positive bacilloscopies, sensitivity, specificity, positive predictive value and negative predictive value were 52.3%, 100%, 100% and 89.7%, respectively whereas accuracy was 90.7%. The IS6110-based PCR for TB diagnosis developed in DNA extracted from a positive smear is a fast, simple, specific, and safe method.

PCR interna con ADN extraído directamente de portaobjetos positivos para confirmar o excluir el diagnóstico de tuberculosis: enfoque en la bioseguridad / In-house PCR with DNA extracted directly from positive slides to confirm or exclude the diagnosis of tuberculosis: focus on biosafety

The possibility to obtain DNA from smears is a valuable alternative to remedy the lack of samples when they are totally used for bacilloscopy; this technique solves the biosafety problem related to a possible accident with the transportation of flasks containing potentially transmissible clinical samples. Hence, the purpose of this study was to utilize the insertion sequence IS6110 for amplification of DNA from a smear-positive sample for tuberculosis (TB) diagnosis. Among the 52 positive bacilloscopies, sensitivity, specificity, positive predictive value and negative predictive value were 52.3%, 100%, 100% and 89.7%, respectively whereas accuracy was 90.7%. The IS6110-based PCR for TB diagnosis developed in DNA extracted from a positive smear is a fast, simple, specific, and safe method

La posibilidad de obtener ADN a partir de frotis es una valiosa alternativa para remediar la falta de muestras cuando estas son totalmente utilizadas para la baciloscopia; esta opción soluciona, además, el problema de bioseguridad asociado a la posibilidad de accidente al transportar frascos que contienen muestras clínicas potencialmente infectivas. Por lo tanto, el propósito de este estudio fue utilizar para el diagnóstico de la tuberculosis la secuencia de inserción IS6110 para amplificación del ADN a partir de frotis que resultaron positivos por baciloscopia. Del análisis de 52 baciloscopias positivas surge que la sensibilidad, la especificidad, el valor predictivo positivo y el valor predictivo negativo de esta técnica fueron, respectivamente, del 52,3%, del 100%, del 100% y del 89,7%; y la precisión fue del 90,7%. La PCR IS6110 para el diagnóstico de tuberculosis, desarrollada con ADN extraído de frotis positivos, es un método rápido, simple, específico y seguro

In-house PCR with DNA extracted directly from positive slides to confirm or exclude the diagnosis of tuberculosis: focus on biosafety. / In-house PCR with DNA extracted directly from positive slides to confirm or exclude the diagnosis of tuberculosis: focus on biosafety.

The possibility to obtain DNA from smears is a valuable alternative to remedy the lack of samples when they are totally used for bacilloscopy; this technique solves the biosafety problem related to a possible accident with the transportation of flasks containing potentially transmissible clinical samples. Hence, the purpose of this study was to utilize the insertion sequence IS6110 for amplification of DNA from a smear-positive sample for tuberculosis (TB) diagnosis. Among the 52 positive bacilloscopies, sensitivity, specificity, positive predictive value and negative predictive value were 52.3

, 100

, 100

and 89.7

, respectively whereas accuracy was 90.7

. The IS6110-based PCR for TB diagnosis developed in DNA extracted from a positive smear is a fast, simple, specific, and safe method.