• Sajjad Iqbal
  • Rashid Ahmed
  • Saleem -uz-Zaman Adhami
  • Asim Mumtaz


Background: Pakistan ranks 8th on the list of 22 high-burden tuberculosis (TB) countries in the worldaccording to the World Health Organization’s (WHO) Global Tuberculosis Control 2009. Includingother reasons the main cause is improper and late diagnosis of the disease. PCR may play an importantrole to control the disease with its rapid, sensitive and specific diagnosis. But in Pakistan due to lake ofknowledge about this latest technique we are not using this technique appropriately. Clinicians still truston conventional methods of TB diagnosis, which are time consuming or insensitive. The present studywas arranged to highlight the importance of PCR in TB diagnosis in pulmonary and extra-pulmonarycases and its comparison with conventional methods. Methods: Samples obtained from 290 patients ofsuspected TB (pulmonary or extra-pulmonary) were subjected to ZN smear examination, LJ mediumculture and PCR test by amplifying 541bp fragment of Mycobacterium tuberculosis complex genome.The present prospective study is performed at Shalamar Hospital Lahore from November 2008 toNovember 2010. Results: A distinctly difference was observed in the test results done by PCR andother conventional techniques in pulmonary or extra-pulmonary tuberculosis samples (p<0.001). Thesensitivity of different tests was 68.62% for PCR, 26.90% for LJ medium culture, and 14.14% for ZNsmear examination (p<0.05). However, there was no significant difference between different tests as foras specificity was concerned. PCR test sensitivity in pulmonary and extra-pulmonary clinical sampleswas 78.34 and 61.76% respectively, being significantly higher (p<0.05) when compared withsensitivity of other tests. The mean detection time for M. tuberculosis was 25 days by LJ mediumculture and less than 1 day by smear examination and PCR test. Conclusion: PCR test is more sensitivethan ZN smear examination and LJ medium culture for the diagnosis of TB in pulmonary and extrapulmonary clinical samples.Keywords: Mycobacterium tuberculosis complex, Polymerase chain reaction, LJ medium culture, ZNstaining.


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