BIOMAT Database Logo BIOMAT Database Logo

The quality of laboratory testing today: an assessment of sigma metrics for analytic quality using performance data from proficiency testing surveys and the CLIA criteria for acceptable performance. 2006

James O Westgard, and Sten A Westgard
Department of Pathology and Laboratory Medicine, University of Wisconsin Medical School, Madison 53706, USA.

To assess the analytic quality of laboratory testing in the United States, we obtained proficiency testing survey results from several national programs that comply with Clinical Laboratory Improvement Amendments (CLIA) regulations. We studied regulated tests (cholesterol, glucose, calcium, fibrinogen, and prothrombin time) and nonregulated tests (international normalized ratio [INR], glycohemoglobin, and prostate-specific antigen [PSA]). Quality was assessed on the sigma scale with a benchmark for minimum process performance of 3 sigma and a goal for world-class quality of 6 sigma. Based on the CLIA criteria for acceptable performance in proficiency testing (allowable total errors [TEa]), the national quality of cholesterol testing (TEa = 10%) estimated sigma values as 2.9 to 3.0; glucose (TEa = 10%), 2.9 to 3.3; calcium (TEa = 1.0 mg/dL), 2.8 to 3.0; prothrombin time (TEa = 15%), 1.8; INR (TEa = 20%), 2.4 to 3.5; fibrinogen (TEa = 20%), 1.8 to 3.2; glycohemoglobin (TEa = 10%), 1.9 to 2.6; and PSA (TEa = 10%), 1.2 to 1.8. The analytic quality of laboratory tests requires improvement in measurement performance and more intensive quality control monitoring than the CLIA minimum of 2 levels per day.

UI MeSH Term Description Entries
D007753 Laboratories Facilities equipped to carry out investigative procedures. Laboratory
D011785 Quality Assurance, Health Care Activities and programs intended to assure or improve the quality of care in either a defined medical setting or a program. The concept includes the assessment or evaluation of the quality of care; identification of problems or shortcomings in the delivery of care; designing activities to overcome these deficiencies; and follow-up monitoring to ensure effectiveness of corrective steps. Quality Assessment, Health Care,Health Care Quality Assessment,Health Care Quality Assurance,Healthcare Quality Assessment,Healthcare Quality Assurance,Quality Assessment, Healthcare,Quality Assurance, Healthcare,Assessment, Healthcare Quality,Assessments, Healthcare Quality,Assurance, Healthcare Quality,Assurances, Healthcare Quality,Healthcare Quality Assessments,Healthcare Quality Assurances,Quality Assessments, Healthcare,Quality Assurances, Healthcare
D011786 Quality Control A system for verifying and maintaining a desired level of quality in a product or process by careful planning, use of proper equipment, continued inspection, and corrective action as required. (Random House Unabridged Dictionary, 2d ed) Control, Quality,Controls, Quality,Quality Controls
D001774 Blood Chemical Analysis An examination of chemicals in the blood. Analysis, Blood Chemical,Chemical Analysis, Blood,Analyses, Blood Chemical,Blood Chemical Analyses,Chemical Analyses, Blood
D003951 Diagnostic Errors Incorrect or incomplete diagnoses following clinical or technical diagnostic procedures. Diagnostic Blind Spots,Errors, Diagnostic,Misdiagnosis,Blind Spot, Diagnostic,Blind Spots, Diagnostic,Diagnostic Blind Spot,Diagnostic Error,Error, Diagnostic,Misdiagnoses
D005161 Facility Regulation and Control Formal voluntary or governmental procedures and standards required of hospitals and health or other facilities to improve operating efficiency, and for the protection of the consumer. Facility Control,Facility Regulation,Regulation, Facility,Control, Facility,Controls, Facility,Facility Controls,Facility Regulations,Regulations, Facility
D006801 Humans Members of the species Homo sapiens. Homo sapiens,Man (Taxonomy),Human,Man, Modern,Modern Man
D015203 Reproducibility of Results The statistical reproducibility of measurements (often in a clinical context), including the testing of instrumentation or techniques to obtain reproducible results. The concept includes reproducibility of physiological measurements, which may be used to develop rules to assess probability or prognosis, or response to a stimulus; reproducibility of occurrence of a condition; and reproducibility of experimental results. Reliability and Validity,Reliability of Result,Reproducibility Of Result,Reproducibility of Finding,Validity of Result,Validity of Results,Face Validity,Reliability (Epidemiology),Reliability of Results,Reproducibility of Findings,Test-Retest Reliability,Validity (Epidemiology),Finding Reproducibilities,Finding Reproducibility,Of Result, Reproducibility,Of Results, Reproducibility,Reliabilities, Test-Retest,Reliability, Test-Retest,Result Reliabilities,Result Reliability,Result Validities,Result Validity,Result, Reproducibility Of,Results, Reproducibility Of,Test Retest Reliability,Validity and Reliability,Validity, Face
D019411 Clinical Laboratory Techniques Techniques used to carry out clinical investigative procedures in the diagnosis and therapy of disease. Clinical Laboratory Test,Clinical Laboratory Testing,Clinical Laboratory Diagnoses,Clinical Laboratory Testings,Clinical Laboratory Tests,Diagnoses and Laboratory Examinations,Diagnosis, Laboratory,Laboratory Diagnosis,Laboratory Examinations and Diagnoses,Laboratory Techniques, Clinical,Clinical Laboratory Technique,Diagnose, Clinical Laboratory,Laboratory Diagnoses,Laboratory Technique, Clinical,Laboratory Test, Clinical,Laboratory Testing, Clinical,Technique, Clinical Laboratory,Test, Clinical Laboratory,Testing, Clinical Laboratory
D019985 Benchmarking Method of measuring performance against established standards of best practice. Benchmarking, Health Care,Benchmarks,Best Practice Analysis,Metrics,Benchmark,Benchmarking, Healthcare,Analysis, Best Practice,Health Care Benchmarking,Healthcare Benchmarking

Related Publications

James O Westgard, and Sten A Westgard
Latent print quality in blind proficiency testing: Using quality metrics to examine laboratory performance.
July 2021, Forensic science international,
James O Westgard, and Sten A Westgard
CLIA requirements for proficiency testing: the basics for laboratory professionals.
September 2013, MLO: medical laboratory observer,
James O Westgard, and Sten A Westgard
Comparative analysis of calculating sigma metrics by a trueness verification proficiency testing-based approach and an internal quality control data inter-laboratory comparison-based approach.
November 2019, Journal of clinical laboratory analysis,
James O Westgard, and Sten A Westgard
Assessing the analytic validity of molecular testing for Huntington disease using data from an external proficiency testing survey.
January 2012, Genetics in medicine : official journal of the American College of Medical Genetics,
James O Westgard, and Sten A Westgard
Analysis of performance of clinical biochemistry laboratory using Sigma metrics and Quality Goal Index.
January 2021, Practical laboratory medicine,
James O Westgard, and Sten A Westgard
Performance evaluation of a coagulation laboratory using Sigma metrics.
July 2018, International journal of health care quality assurance,
James O Westgard, and Sten A Westgard
Sigma-Metrics of Electrolyte Tests From a Recently Launched New-Generation Proficiency Testing Program of the Korean Association of Quality Assurance for Clinical Laboratory.
July 2017, Annals of laboratory medicine,
James O Westgard, and Sten A Westgard
Assessment of hematology laboratory performance in the total testing process using quality indicators and sigma metrics in the northwest of Ethiopia: A cross-sectional study.
January 2024, Health science reports,
James O Westgard, and Sten A Westgard
European specifications for imprecision and inaccuracy compared with US CLIA proficiency-testing criteria.
January 1995, Clinical chemistry,
James O Westgard, and Sten A Westgard
Review of actual proficiency-testing performance under CLIA '67 (March 14, 1990) rules: perspective from the first year's data.
July 1992, Clinical chemistry,
Copied contents to your clipboard!