Tuberculosis remains one of the leading causes of mortality worldwide. Microscopy and culture still the references of Tuberculosis diagnosis. Microscopy has a low sensitivity, specificity and culture is time consuming. For this reason, rapid and reliable diagnosis of the disease is required. We describe a retrospective comparison study of tuberculosis diagnosis by PCR IS6110 directly from blood samples of patients with suspected Tuberculosis with Acid-Fast-Bacilli and culture. From 80 patients enrolled, culture results were positive for 25, acid fast bacilli were positive for 15 and blood PCR were positive for 45. Comparing blood PCR result with acid fast bacilli, the sensitivity and specificity were respectively 35% and 87.5% (PPV = 9%, PNV = 21.1%) for PTB. The specificity of blood PCR was 100% (PNV = 72.73%), for EPTB. In comparison with culture blood PCR have a high sensitivity and specificity better than with the acid fast, they were respectively 57.89%, 100% for PTB and 50%, 100% for EPTB. This study is the first established in Tunisia and in Africa aiming to diagnose TB from blood. B-PCR results has shown a high correlation with culture that illustrates the usefulness of B-PCR as a rapid and early diagnostic, combined with others serological results B-PCR can be a solid, rapid and efficient TB diagnostic tools.
Keywords: laboratories; microbiology; molecular biology.