Analytic bias among certified methods for the measurement of hemoglobin A1c: a cause for concern?

We studied the magnitude, significance, and origin of an analytic bias that emerged between our point-of-care (POC) and our central laboratory (CL) methods for the measurement of hemoglobin A1c (HbA1c) and evaluated the analytic accuracy of 7 commonly used HbA1c methods relative to the National Glycohemoglobin Standardization Program (NGSP) reference method. The POC and CL methods were compared by split-sample analysis of clinical specimens and time series analyses of the HbA1c results reported for a 33-month period. The relative accuracies of 7 HbA1c methods were evaluated using College of American Pathologists proficiency survey results. Long-term drifts in the CL- and POC-analyzed test results caused the median intermethod bias [(POC result)-(CL result)] to increase from -0.4% to -0.9% HbA1c. Systematic biases, drifts in analytic performance over time, and intermethod variability were frequently observed among the 7 NGSP-certified HbA1c methods. Intermethod variability is a potential source of inaccuracy whenever HbA1c results are interpreted relative to universal, fixed, clinical decision thresholds.

The Missing Link: Connection Is the Key to Resilience in Medical Education.

Awareness of the risks of burnout, depression, learner mistreatment, and suboptimal learning environments is increasing in academic medicine. A growing wellness and resilience movement has emerged in response to these disturbing trends; however, efforts to address threats to physician resilience have often emphasized strategies to improve life outside of work, with less attention paid to the role of belonging and connection at work. In this Commentary the authors propose that connection to colleagues, patients, and profession is fundamental to medical learners' resilience, highlighting "social resilience" as a key factor in overall well-being. They outline three specific forces that drive disconnection in medical education: the impact of shift work, the impact of the electronic medical record, and the impact of "work-life balance." Finally, the authors propose ways to overcome these forces in order to build meaningful connection and enhanced resilience in a new era of medicine.

Analytical variability among methods for the measurement of 25-hydroxyvitamin D: still adding to the noise.

OBJECTIVES: To compare total 25-hydroxyvitamin D [25(OH) D] results measured by 3 direct immunoassays, including the previous version of the DiaSorin Liaison2 assay and the current versions of the Siemens Centaur2 and the Abbott Architect assays, with results measured in serum extracts by liquid chromatography/tandem mass spectrometry (LC/MS) and radioimmunoassay (RIA). METHODS: Our study sample consisted of 163 consecutive clinical specimens submitted to our laboratory for 25(OH)D testing. RESULTS: Regression and bias analyses of the data revealed that results measured by the 3 direct immunoassay methods had high degrees of random variability and bias relative to the results determined by LC/MS and RIA. The relative biases between results measured by the direct assays and the comparison methods exceeded a recommended criterion for the total allowable error of a 25(OH)D test in as many as 48% of our clinical specimens. Of the subjects in our study sample, 33, 37, 30, 45, and 71 were classified as vitamin D deficient based on results determined by LC/MS, RIA, Liaison2, Architect, and Centaur2, respectively. CONCLUSIONS: Intermethod variability in 25(OH)D assays continues to limit our progress toward the establishment of reference values for 25(OH)D in health and our efforts to gain a better understanding of the role of vitamin D insufficiency as a risk factor for disease.