How better is random blinded re‑checking results in Revised National TB Control Programme, India.

Background: The Revised National Tuberculosis Control Programme (RNTCP) is implementing the External Quality assurance (EQA) and Random blinded re-checking (RBRC) as one of its important component. This nationwide study was conducted to determine (1) the number and types of RBRC errors and (2) the sensitivity and specificity among rechecked slides. Materials and Methods: The study was based on the monthly RBRC reports submitted by ~13,000 designated microscopy centres (DMCs) across the country under routine programmatic settings in 2010. The DMCs reports were compiled at district, state and national level. Results: A total of 11, 89,564 slides were rechecked from 11,039 DMCs. Of which 99.5% of rechecked slides did not have any errors. The sensitivity and specificity of the rechecked slides had 98% sensitivity and 100% specificity. Conclusion: RBRC is the crucial component of EQA and the results from the programme are found to be satisfactory. Based on the study findings, the earlier value of 80% sensitivity used for calculation of annual sample size for RBRC has been increased to 90% sensitivity. The annual RBRC sample size for DMCs has been increased by 1.5–2 folds.