A Comparative Study of Auramine Staining Using Light Emitting Diode (LED) Fluorescent Microscopy with Ziehl-Neelsen Staining for Detection of Acid Fast Bacilli in Sputum in a Tertiary Care Hospital, Karimnagar

Tuberculosis (TB) still remains a global health problem affecting one third of world population. Early diagnosis of TB is very important for therapeutic reasons and to control the spread of infection. For developing countries with a large number of cases and financial constraints, evaluation of rapid and inexpensive diagnostic methods has a great importance. Aim of this research is to study the efficacy of Ziehl Neelsen (ZN) method versus fluorescent staining in the detection of acid fast bacilli (AFB) in sputum samples. A total of 675 sputum samples collected from suspected cases of pulmonary tuberculosis which were subjected to Ziehl Neelsen and fluorescent auramine O (AO) staining for the detection of acid fast bacilli. Out of 675 samples, 58 (8.59%) were positive for AFB on the Ziehl Neelsen method, while the positivity increased to 93 (13.77%) on the fluorescent AO method. AO was found to be superior to Ziehl Neelsen on several aspects. AO staining was able to detect more paucibacillary than Ziehl Neelsen staining. Since screening was done under lower power of magnification (400x), fluorescent AO technique has a better diagnostic value and is less time consuming compared to Ziehl Neelsen in diagnosing pulmonary tuberculosis patients. Hence, the efficacy of AO staining under fluorescence microscopy proved to be much higher than Ziehl Neelsen staining under conventional light microscopy.