A Novel Approach for Routinely Assessing Laboratory Sigma Metrics for a Broad Range of Automated Assays

Area of Science:

• Clinical Chemistry
• Laboratory Quality Management
• Assay Performance Evaluation

Background:

• Sigma metrics are used in clinical laboratories to evaluate assay performance based on accuracy, precision, and allowable total error.
• Higher Sigma metric values signify superior process performance.
• Previous studies often assessed Sigma metrics on limited, highly controlled systems.

Purpose of the Study:

• To develop and validate a methodology for deriving a single Sigma metric for numerous analytes across multiple clinical laboratory systems.
• To assess the performance of clinical laboratory assays in real-world settings using Sigma metrics.

Main Methods:

• An algorithm was created to extract quality control (QC) data from the QuidelOrtho E-Connectivity® database for 115 analytes.
• Sigma metrics were calculated for each analyte using the extracted QC data.
• The median Sigma metric was determined for each assay to represent overall performance.

Main Results:

• Out of 115 analytes, 79 (68.7%) achieved a Sigma metric of 6 or higher.
• A total of 98 out of 115 analytes (85.2%) reached a Sigma metric of 5 or higher.
• These high Sigma levels were observed despite inherent laboratory and instrument variabilities.

Conclusions:

• A novel methodology was established to consolidate Sigma metrics from hundreds of analyzers into a single assay quality indicator.
• This approach provides a baseline for understanding assay performance in diverse, real-world laboratory conditions.
• The study highlights that a majority of assays demonstrate high Sigma performance, even when accounting for variations in lab environment, instrumentation, materials, and reagents.