Evaluation Of Fluorescein Diacetate (FDA) Vital Staining In Detecting Viable Acid Fast Bacilli In Comparison With Culture In A Tertiary Care Hospital

Abstract

Background: Peripheral laboratories in developing countries usually lack the facilities of culture and drug susceptibility testing and mostly relay on smear microscopy which is used as a basic tool in diagnosis of Tuberculosis. But the routinely used microscopic techniques such as ZN staining and Fluorescent microscopy cannot discriminate the live and dead bacilli.

Objectives: Hence, this study is aimed to evaluate Fluorescein diacetate (FDA) vital staining technique in detection of viable acid fast bacilli among smear positive sputum samples from a tertiary care hospital situated in Mysuru, South India.

Results: A total of 142 smear positive sputum samples were subjected to Auramine staining, FDA staining and Culture on LJ-Media . Considering culture as gold standard, FDA staining had a sensitivity of 99.14% and specificity of 96.43%. Positive predictive value, Negative predictive value of FDA staining was 99.14 and 96.43% respectively. Diagnostic accuracy of FDA staining in our study was found to be 98.61%.

Conclusion: Implementation of FDA staining in peripheral laboratories with limited access to culture and drug susceptibility testing would help in minimizing the culture and drug susceptibility testing load in referral centres.