Mycobacterium tuberculosis detection in blood using multiplex nested polymerase chain reaction

SETTING: 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. OBJECTIVE: Evaluation of the Blacklight (R) 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. DESIGN: 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. results: Of 130 cases, PCR was positive in 22 sampies (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%. CONCLUSION: 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.