• Mumtaz Ahmad Khan
  • Sajjad Hussain Mirza
  • Shahid Ahmed Abbasi
  • Tariq Butt
  • Masood Anwar


Background. The rapid diagnosis of infectious diseases, particularly those that represent a publichealth problem, like tuberculosis, is a challenging problem. By using nucleic acid amplificationtechniques like PCR, one may be able to diagnose, the disease on the day of arrival of specimen inthe laboratory. For diagnosis of tuberculosis by direct methods like PCR, specimens from site ofinfection are required. In certain cases it is difficult to get the specimens from site of infection andin such situations; some researchers have tried to detect the DNA of Mycobacterium tuberculosiscomplex from blood of these patients. The purposive of this study is to determine the diagnosticefficacy of peripheral blood-based polymerase chain reaction for diagnosis of pulmonarytuberculosis. Methods. This was a simple descriptive study, carried out in Department ofMicrobiology, Armed Forces Institute of Pathology, Rawalpindi from Jan 2004 to Dec 2004.Sputum and blood samples were collected from 96 suspected patients of pulmonary tuberculosis.Sputum samples processed for ZN staining and AFB culture (gold standard) and blood samplesprocessed for PCR. Results. Out of 96 cases, 60 (62.5%) were culture positive. PCR was positivein 14 (14.5%). AFB smear positive were 34 (35.4%). The overall sensitivity and specificity of thePCR assay was 20% and 94.4% respectively and the positive and negative predictive values were85.71% and 41.46% respectively. The overall efficiency of the test was 47.91%. Conclusion. Dueto low sensitivity; a negative PCR assay does not rule the disease. However, this test may behelpful in cases where specimens from the site of infection are not available.Key Words: PCR, peripheral blood, pulmonary tuberculosis


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