Same-day sputum smear microscopy for the diagnosis of pulmonary tuberculosis – Light-emitting diode fluorescent staining with direct sputum versus Ziehl–Neelsen staining with concentration sputum

Abstract

OBJECTIVE: The objective of the study was to evaluate the utility of fluorescent staining (FS) technique with direct sputum for the diagnosis of pulmonary tuberculosis (TB). MATERIALS AND METHODS: Three sputum specimens (spot, second spot, and morning) were collected from the study participants. One smear was prepared from the direct sample and one using the N-acetyl-L-cysteine-sodium hydroxide concentration method. The direct smears were stained using FS, and Ziehl–Neelsen (ZN) staining was used to stain smears prepared after concentration method. Smear results were pooled and compared in two categories: standard spot-morning and same-day smears. The Chi-square test was used to evaluate the statistical difference in smear-positive cases. RESULTS: Among 2922 participants included in the study, smear positivity was, respectively, 10.5% and 10.2% for FS and ZN smears using spot-morning approach. Using the same-day approach, the smear positivity was, respectively, 10.4% and 9.9% for FS and ZN smears; statistically, the difference was not statistically significant (P > 0.05) between the staining techniques in both the approaches. CONCLUSION: More smear positivity is the advantage of using FS technique. Given this advantage, National TB Control Programs of high-TB-burden countries should consider installing light-emitting diode FS technique in peripheral settings also.