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Objective: To evaluate false negativity rate of Ziehl-Neelson smear microscopy. Methodology: This descriptive study was performed at Mycobacteriology laboratory of Holy Family Hospital, Rawalpindi during June 2017 to March 2018. 3951 was study sample. Out of these 3951 cases, 2773 cases had pulmonary tuberculosis while 1178 were extra pulmonary tuberculosis cases. Study population was selected from suspected cases of tuberculosis referred to laboratories from the outdoor clinic of pulmonology as well as internal medicine department and neighboring referral health facilities. Follow up cases were not included in study sample. LJ media was considered the standard to test the false negativity rate of ZN smear microscopy. Results: Most common sample was sputum 48.5%, followed by pleural fluid 12% and pus 8.3%, respectively. 23.1% samples were false negative out of which pulmonary samples were 19.6% and extra pulmonary samples were 29.2%. P value was statistically significant Conclusion: ZN staining technique has high false negativity rate, especially in patients with low mycobacterial load. National TB control program should adopt more efficient diagnostic methods for diagnosing tuberculosis instead of ZN staining. Keywords: Tuberculosis, Ziehl-Neelson Smear, False negative, Microscopy. |
