Errors, mistakes, blunders, outliers, or unacceptable results: how many?

Abstract

We have studied 219 353 individual clinical chemistry results obtained in methods comparison studies. Each result was prospectively compared with its replicate, comparative, or repeat value to identify differences from expected values. Unacceptable results were defined as differing from the expected values by ≤7 SDs or CVs. We believe these differences represent special-cause variation and should be expressed as unacceptable rates per million results (ppm). We observed 447 ppm unacceptables: 196 ppm in control samples and 251 ppm in patients’ samples. Results judged likely to alter patient care occurred at a rate of 41 ppm. To better understand the magnitude of these rates, we compared these results with reports of error rates in HIV testing and the airline industry. The measurements reported were made for the purpose of quality improvement, not judgment or discovery. The significance of these findings for laboratorians, manufacturers, and regulators is discussed.

Highly accurate molecular genetic testing for HFE hereditary hemochromatosis: results from 10 years of blinded proficiency surveys by the College of American Pathologists

“…In addition, these published analytical error rates for molecular genetic tests are quite comparable to those found for other more automated diagnostic analytes in laboratory medicine, with well-documented analytical error rates ranging from 0.01 to 5%. [30][31][32][33][34][35][36] Prior publications have also documented findings analogous to this study concerning a higher variability in interpretive (compared with analytical) performance, with interpretive accuracy rates ranging from 92.5% for BRCA1/2 (ref. 25) to 99.7% for familial dysautonomia.…”

Evaluation of analytical errors in a clinical chemistry laboratory: A 3 year experience

“…Many studies have emphasized that these activities impact positively in reducing analytical errors. [ 8 9 10 ] In our quest to further increase analytical precision and accuracy, we enrolled our laboratory in External Quality Assurance Programs. This demands that results are analyzed periodically during the course of work and any observed shortcomings promptly addressed.…”

Patient pools and the use of “patient means” are valuable tools in quality control illustrated by a bone-specific alkaline phosphatase assay

“…For the clinical use of blood tests, it is essential that results are reliable and accurate, which is why quality control (QC) has become the cornerstone of clinical biochemistry. QC must be able to detect analytical errors that can potentially lead to harm in patients [1][2][3].…”