Evaluation of Random Blinded Re-Checking of AFB Slides under Revised National Tuberculosis Control Programme in Solapur District

Abstract

Background: One of the important components of revised national tuberculosis control programme is ‘Good quality diagnosis, primarily by sputum smear microscopy’. All efforts are made to ensure that the designated microscopy centers function at optimal level. The process of ‘Random Blinded Re-Checking’ (RBRC)of Acid Fast Bacillus slides is built in the programme. Objectives: To study the relationship of different types of errors detected in RBRC with respect to time, place and cost. To study the stability and capability of the process of RBRC. Methods: Analysis of secondary data of external quality assessment of Solapur district since January 2006 is supplemented by direct implementation of the programme since April 2011 till date. Data analysis is done using statistical software Minitab version 16.Results: Since January 2006 to May 2012;42191 slides were re-checked in 77 RBRC sessions at District Tuberculosis Center, Solapur.Different types of 69 errors were detected. Onsite evaluation and panel testing did not show any discordance. Barshi and Mangalwedha Tuberculosis Units (TU) showed significantly higher number of errors as compared to Karmala TU. (P<0.002) Weighted Pareto Chart revealed that the costliest form of errors is high false negatives and low false negatives. Conclusion:Detection of errors in RBRC sessions follows Poisson distribution. The process of RBRC is found to be in control and capable of achieving the desired target of detection of errors.

Keywords

• DPU- Defects per unit
• HFN- High false negative
• RBRC- Random blinded re-checking