Comparison between Light Emitting Diode (LED) Fluorescence Microscopy and Conventional Light Microscopy in the Diagnosis of Pulmonary Tuberculosis

Abstract

Background: Diagnosis of pulmonary tuberculosis is confirmed by sputum microscopy. Sputum can be stained by Ziehl-Neelsen (Z-N) staining and examined by conventional light microscopy. Again it can also be stained with Auramine O stain and examined by light emitting diode (LED) fluorescence microscopy. This study was planned to find the most sensitive, specific and feasible technique for the diagnosis of pulmonary tuberculosis. Materials and Method: This cross-sectional analytical study was conducted in the department of Medicine in collaboration with the department of Microbiology, Sylhet M.A.G. Osmani medical college, Sylhet from 1st January, 2019 to 30th June, 2019. All clinically suspected patients with pulmonary tuberculosis attending both outpatient and inpatient department of Medicine Sylhet M.A.G Osmani medical college hospital, Sylhet during the study period were the study population. Total 380 patients were recruited as study sample after fulfilling the inclusion and exclusion criteria by purposive sampling method. All the patients were referred to department of Microbiology, Sylhet M.A.G Osmani medical college for sputum for AFB examination. All the samples were divided in to two portion and then one portion was marked as group-A-and another portion as group-B. In group-A, conventional Ziehl Neelsen (Z-N) staining with light microscopy and in group-B, Auramine staining with LED fluorescent microscopy were done. Result: Among 380 patients, 47 (12.4%) patients and 52(13.7%) patients were diagnosed as pulmonary tuberculosis by Z-N method and LED fluorescence microscopy respectively but this difference was not significant (*Z=-0.532; p>0.05). Paucibacillary (scanty and 1+) cases were observed more in LED 34 (8.9%) method in comparison to Z-N 31 (8.2%) method. But this difference again did not reach the level of significance (*Z=0.345; p>0.05). But the time required to read the smear by LED method (6.30 ± 0.33 minutes) was significantly shorter than that of Z-N method (3.01 ± 0.27 minutes) (t=561.146; *p<0.001). Conclusion: LED fluorescence microscopy is better than conventional light microscopy in consideration of time taken to finalize result.