Mansoor-ud Din Sajid, Muhammad Siddique, Abdur Rehman, Muhammad Yaqoob.
Role of Sputum Smear in Predicting Culture Results in Pulmonary Tuberculosis.
Pak J Med Health Sci Jan ;8(1):60-2.

Aim: To determine the role of sputum smear in predicting the culture results in pulmonary tuberculosis. Study Design: Cross sectional study Place and duration: Rashid Latif Medical College and CMH, Lahore from Jan 2009 to Dec 2012 Methods: A total of 200 patients with positive sputum smear and sputum culture were selected by non probability convenient sampling but 20 patients lost to follow up and excluded from study. All the patients were given standard 04 drugs anti tuberculosis treatment in the intensive phase and Isoniazid (INH), Rifampicin and Myambutol in continuation phase. Sputum smear examination and culture was performed in every patient at end of second month of treatment. Results: Out of 180 patients 129(71.7%) were male and 51(28.3%) were females. At two months 108(60%) patients were Sputum smear negative and 72(40%) were smear positive. Out of 108 smear negative patients 93(86.1%) were culture negative and 15(13.9%) were culture positive (p<0.005). Out of smear positive patients 48(66.7%) were culture positive and 24(33.3%) were culture negative (p<0.005). Sensitivity and specificity of 02 months sputum smear in predicting the culture conversion is 76.19% and 79.49% respectively. Conclusion: The sensitivity, specificity, positive predictive value and negative predictive value of sputum smear examination in predicting the sputum culture result, are quite low. Sputum smear examination cannot be used as a substitute for sputum culture conversion at two months. However a negative sputum smear at two months is a strong predictor of culture negativity.

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