Same day sputum smear microscopy for the diagnosis of pulmonary tuberculosis: Ziehl-Neelsen versus fluorescent staining

Abstract

Background: Sputum smear microscopy is the main tool for the diagnosis of pulmonary tuberculosis (TB), especially in low- and middle-income countries (LMICs). Limited sensitivity of smear microscopy and patient dropouts (PDs) are the important obstacles of national TB control programs. Objectives: (1) To assess the diagnostic utility of the same day (SS2) approach (2) To compare the smear results of the spot morning (SM) and the SS2 approaches. Materials and Methods: The study was conducted in the Department of Microbiology, GSL Medical College, Rajahmundry, Andhra Pradesh, India from January 2011 to February 2015. Three sputum samples were collected [spot (S), second spot (S2) 1 h after S, and morning sample (M)] from the volunteers. The sputum smears were stained by Ziehl-Neelsen (ZN), modified ZN (MZN), and fluorescent staining (FS) techniques and the results were pooled and compared under SM and SS2 approaches. Results: Of the 3,186 study participants, sputum smear positivity (SSP) for SM approach was 9.6% and 10.8% and for SS2 approach, it was 9.4% and 10.6%, respectively, with ZN and FS and the results were statistically insignificant (Mann-Whitney U test, P > 0.05). Conclusion: Technically SSP was similar for both the approaches and no improvement was observed with the SS2 approach. Hence, there is an urgent need to improve SSP.

Keywords

• Fluorescent staining
• patient dropouts
• spot morning approach
• sputum smear positivity
• same day (SS2) approach
• Ziehl-Neelsen staining