Shazia Tariq, Maria Khan, Quratulain Tariq, Valeed Khan, Naima Tariq, Haroon Tariq, Tariq Ahmed.
Conventional diagnosis for tuberculosis versus latest modalities at a tertiary care setting of Peshawar.
J Med Sci May ;28(1):29-33.

Objective: To evaluate and compare the performance of Ziehl Neelsen (ZN) smearing, Lowenstein-Jensen (LJ) culture and real-time PCR analysis to detect Mycobacterium tuberculosis in pulmonary and extra-pulmonary specimens.Materials and Methods: A descriptive study conducted from January 2016 through December 2018, on a total of 293 clinical samples of patients suspected with pulmonary and extra-pulmonary tuberculosis at a tertiary hospital of Peshawar, Pakistan. Specimens were processed by ZN smearing, LJ culture and Real-time PCR technique for the detection of M.tuberculosis. The target for the amplification was a segment of IS6110 in the M.tuberculosis chromosome. Specificity and sensitivity were derived for each test and Fishers exact test was performed to examine significance of association between specimen types and each test. Results: Of the 293 samples, 165(56.3%) were from males and 128(43.7%) females. Mean age was 44 years (2-85 years). Specimen types included: CSF (30.4%), pleural fluid (4.1%), sputum (15%), urine (2.4%), synovial fluid (2.4%), other fluids (33.1%) and biopsies (12.6%). Using PCR as gold standard, ZN microscopy correctly identified 20.5% of total M.TB positive specimens and LJ culture detected 47.7%.Certain specimen types showed higher positivity rates of M.TB detection: synovial fluid (42.9%), pleural fluid (41.7%)by PCR analysis. ZN microscopy was associated with the low positivity rates for all speci-mens, the highest being 18.2% for sputum samples. Conclusion: Tuberculosis PCR is a more rapid and reliable test in the diagnosis and management of tuberculosis. Both Pul-monary and extra-pulmonary specimens exhibit greater positivity rates by PCR analysis than by LJ culture and ZN smearing.

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