<I>Mycobacterium tuberculosis</I> detection in blood using multiplex nested polymerase chain reaction

Abstract

Polymerase chain reaction (PCR) offers great promise for the rapid, sensitive and specific diagnosis of tuberculosis (TB). However, blood TB PCR is still not standardised. Evaluation of the Blacklight® Card to standardise TB PCR in blood samples using a multiplex nested PCR method targeting insertion sequence 6110 and MPB64 sequence for use as an auxiliary tool in the diagnosis of TB. The study focused on the standardisation of the Blacklight Card as a new extraction tool and its evaluation using 130 blood samples randomly collected from patients with clinical symptoms of TB. Of 130 cases, PCR was positive in 22 samples (17%). The overall sensitivity and specificity of the PCR assay was respectively 95.7% and 100%; the positive and negative predictive values were respectively 85.1% and 99.2%. These results suggest that for the detection of Mycobacterium tuberculosis DNA in peripheral blood mononuclear cells, the Blacklight Card may be a useful tool for the rapid diagnosis of disseminated and extra-pulmonary forms of TB as well as in difficult-to-diagnose cases in which a diagnosis is urgently needed due to the severity of the patient's status.