Assessment of Analytical Quality in Clinical Laboratory Using Sigma Metrics

Evaluation of analytical reliability based on variance index score, measurement uncertainty and root cause analysis in a 2-year external quality assessment scheme

This retrospective analytical study evaluated EQAS results generated over 2 years in a National Accreditation Board for Testing and Calibration Laboratories-accredited tertiary-care clinical biochemistry laboratory, finding routine chemistry, electrolyte and immunoassay parameters demonstrated predominantly good to excellent VIS and MU performance.

Sigma metric and Quality Goal Index assessment of hemoglobin A1c analytical performance in an ambulatory accredited laboratory.

Analytical Performance Specifications Derived from External Quality Assessment Data: Comparison with Biological Variation-Based Models for Intermediate Precision Assessment.

Background Analytical performance specifications (APSs) are essential for quality management in medical laboratories. Considering the discrepancies between laboratory performance and existing guidelines, lack of consideration of concentration-dependent variability, and absence of recommendations for certain parameters, we aimed to define APSs for internal use in biochemistry, hemostasis, and hematology based on external quality assessment (EQA) peer group data and evaluate their suitability for intermediate precision assessment versus biological variation (BV)-based APSs. Methods EQA-based allowable CV (CVallowable) was estimated from pooled CVs derived from EQA peer group results. Allowable bias, expanded measurement uncertainty, and total allowable error were calculated. CVallowable targets were assessed using intermediate precision data from different analytical systems within a laboratory group and compared with BV-based APSs. Concordance between theoretical specifications derived from mathematical models and observed analytical performance (AP) was evaluated using (i) the proportion of internal QC CVs meeting the predefined CVallowable across laboratories and (ii) observed analytical imprecision expressed as a percentage of the allowable imprecision budget. Results APSs were established for 110 biochemical analytes, 23 hemostasis parameters, and 28 hematology parameters across different concentration ranges. EQA-derived APSs agreed with observed intermediate precision for 102 biochemical, 14 hemostasis, and 24 hematology parameters. BV-based APSs showed agreement for only 49 biochemical, two hemostasis, and 11 hematology parameters, while overly restrictive goals or lack of agreement were observed for several analytes. Conclusions APSs derived from pooled EQA peer group data provide realistic and technically achievable intermediate precision targets consistent with current AP and thus can complement BV-based specifications.

The Incidence and Evaluation of Quality Indicators for Patient Safety Across the Total Testing Process in the Clinical Laboratory

Introduction: Quality indicators (QIs) are useful evaluation tools that enable the identification of clinical laboratory performance levels and can be used to assess critical healthcare dimensions depending on the objective measures. Standardized and recognized QIs are used to monitor clinical laboratory errors and to manage the risk in diagnostic testing (Grecu et al., 2014, as cited in Alshaghdali et al., 2022).  Aim: The aim of this secondary research is to review the frequency of clinical laboratory errors and to determine the need to continually conduct critical research on the analytical stage even in the phase of automation and modern technologies.  Method: Literature searches were conducted through Google Scholar, PubMed, Scopus and Scielo to retrieve studies published from 10 years ago but only 9 studies from year 2020 were used for the analysis. Critical Appraisal Skills Program (CASP) tool was used to select the studies based on predefined criteria.

Risk-based redesign of internal quality control procedures for emergency immunoassays in clinical laboratories: a multicenter study from China

Baseline IQC practices for emergency immunoassays in the surveyed laboratories were inconsistent and lacked a standardized risk-based foundation, and it is recommended that clinical laboratories implement individualized RB-SQC protocols designed using the Westgard Sigma Rule with Run Length nomogram, and periodically reassess their appropriateness based on updated sigma metrics.

Assessing laboratory performance for markers of kidney injury/function: a retrospective study based on External Quality Assessment

Abstract Background: Chronic kidney disease (CKD) and acute kidney injury (AKI) affect over 850 million individuals worldwide, with diagnosis and management heavily dependent on laboratory biomarkers. Reliable assessment of kidney biomarkers is therefore essential. External Quality Assessment (EQA) plays a critical role in ensuring the accuracy and comparability of results across laboratories. Methods: We retrospectively analyzed EQA data from a Brazilian proficiency testing provider (January 2009–March 2024). Reported results for serum creatinine, urinary creatinine, urinary albumin, and total urinary proteins were evaluated. Coefficients of variation (CVs) and adequacy percentages (%Adequacy) were compared across methods using the Kruskal–Wallis test. Trends were assessed with the Mann–Kendall test. Results: For serum and urinary creatinine, amidinohydrolase/oxidase methods consistently showed the lowest CVs (~3–4.5%) compared with Jaffé-based methods. For urinary albumin, turbidimetry demonstrated superior performance (~5.0% CV), while for total urinary proteins, benzethonium chloride methods yielded the best results (~5.0% CV). Across all biomarkers, CVs decreased and %Adequacy increased significantly over the 15-year period, particularly at clinically relevant concentrations. Nevertheless, Jaffé-based creatinine methods remained predominant despite their well-documented specificity limitations. Conclusion: Over 15 years, participant laboratories improved the precision and adequacy of kidney biomarker measurements in EQA programs. However, persistent reliance on outdated Jaffé-based creatinine methods compromises standardization and clinical reliability. Adoption of more specific methods and participation in clinically relevant EQA programs are essential to further strengthen laboratory quality and patient safety.