Quality assurance studies in eight State tuberculosis laboratories in India

Area of Science:

• Medical diagnostics
• Microbiology
• Public health

Background:

• Sputum smear microscopy is a cornerstone for tuberculosis diagnosis.
• Ensuring consistent quality in diagnostic testing is crucial for effective patient management and disease control.

Purpose of the Study:

• To evaluate the performance and quality assurance of sputum smear microscopy.
• To assess the consistency and agreement of results across multiple state-level laboratories in India.

Main Methods:

• A proficiency testing program was implemented using coded panels of stained sputum smears.
• Eight state-level laboratories participated, receiving slide panels at 6-month intervals over five rounds.
• Results were analyzed for positive/negative consistency, overall agreement, false positives, and false negatives.

Main Results:

• Positive consistency varied widely (38%-100%), indicating under-reading at some sites.
• Negative consistency was generally high, with most readers achieving 100%.
• Overall agreement exceeded 90% at seven of eight centers, but false-negative rates showed considerable variation (3%-52%).

Conclusions:

• The study effectively evaluated laboratory performance and identified specific weaknesses in the proficiency testing system.
• Findings underscore the need for targeted interventions to improve sputum smear microscopy quality and reduce diagnostic errors.