Abstract Background Ensuring high diagnostic accuracy in pathology laboratories is critical for effective patient care and informed clinical decision-making. The Six Sigma methodology provides a structured approach to evaluate and improve laboratory quality by identifying inefficiencies and reducing errors. This study aimed to assess key quality indicators (QIs) using the Sigma matrix at Gunjan Lab LLP, a standalone pathology lab in Bharuch, India, serving predominantly walk-in patients (95%). Methods The lab, comprising one central processing unit and seven collection centers, collected data from 2023 and 2024 across the pre-analytical, analytical, and post-analytical phases. Selected QIs included: Pre-analytical phase Missed tests, incorrect or extra test selection during registration, demographic errors, sample rejection rates, incorrect patient selection, and phlebotomy errors (e.g., double pricks, needle injuries). Analytical phase Internal Quality Control (IQC) and External Quality Assurance Scheme (EQAS) outliers (3 SD). Post-analytical phase Turnaround time deviations and revised reports. Defects Per Million (DPM) calculations were used to evaluate these indicators and determine Sigma values. Results The analysis revealed Sigma values for missed tests, incorrect test selection, demographic errors, sample rejection rates, and incorrect patient selection ranging between 4.0 and 5.5. However, phlebotomy errors, such as double pricks, had Sigma scores below 4 at five collection centers. Both the analytical and post-analytical phases demonstrated Sigma values between 4.0 and 5.5. Conclusion The Sigma matrix proved to be an effective tool for quality management, enabling data-driven decisions to enhance workflow efficiency and reduce errors. By implementing targeted corrective actions based on these findings, laboratories can achieve continuous quality improvement, ensuring greater diagnostic reliability and patient safety.
Patel et al. (2025) studied this question.