How better is random blinded re-checking results in revised national TB Control Programme, India?

Area of Science:

• Public Health
• Microbiology
• Quality Assurance

Background:

• The Revised National Tuberculosis Control Programme (RNTCP) incorporates External Quality Assurance (EQA) and Random Blinded Re-checking (RBRC).
• This study assessed RBRC error types, sensitivity, and specificity within the RNTCP.

Purpose of the Study:

• To determine the frequency and nature of RBRC errors.
• To evaluate the sensitivity and specificity of slide re-checking in a national TB control program.

Main Methods:

• Analysis of monthly RBRC reports from approximately 13,000 Designated Microscopy Centres (DMCs) nationwide in 2010.
• Compilation of DMC reports at district, state, and national levels for comprehensive review.

Main Results:

• Over 1.1 million slides were rechecked from 11,039 DMCs.
• A minimal error rate was observed, with 99.5% of rechecked slides having no errors.
• High diagnostic accuracy was confirmed, showing 98% sensitivity and 100% specificity.

Conclusions:

• Random Blinded Re-checking (RBRC) is a vital component of External Quality Assurance (EQA) in TB control.
• The RNTCP's RBRC program demonstrated satisfactory performance.
• The study led to an increase in the assumed sensitivity for RBRC sample size calculation from 80% to 90%, and a 1.5-2 fold increase in annual RBRC sample size.