Got HbA1c quality?

Posted by Sten Westgard

This month, Dr. Westgard was teaching his spring semester class for the University of Wisconsin Medical Technology school. He likes to use recently published papers in the scientific literature as a way to relate his lessons to things happening in the "real world" of the laboratory.

This semester, he has written up a number of lessons covering HbA1c methods, performance, and quality requirements based on the article in Clinical Chemistry, Few Point-of-Care Hemoglobin A1c Assay Methods Meet Clinical Needs, by David E. Bruns1 and James C. Boyd and a study by Lenters-Westra and Slingerland (Six out of eight hemoglobin A1c point-of care instruments do not meet the generally accepted analytical performance criteria. Clin Chem 2010;56:44 –52.)

For your convenience, here are the lessons in order...

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• Episode 1 identifies an abstract from the 2009 AACC national meeting [1], a validation study published in the January 2010 issue of Clinical Chemistry [2], and an accompanying editorial in that same issue [3].
• Episode 2 discusses the information available in the abstract and concluded that any decision on acceptable performance depended on knowing the quality needed for the clinical use of a HbA1c test. 
• Episode 3 reviews the recommendations for quality requirements, as discussed by Bruns and Boyd in their editorial [3] that accompanied the publication of the evaluation study by Lenters-Westra and Slingerland [2]
• Episode 4 discusses the study by Lenters-Westra and Slingerland.
• Episode 5, Dr. Craig Foreback provides a discussion of measurement principles to help us understand both the NGSP certification protocol and the use of 3 different secondary reference methods in the Lenters-Westra and Slingerland study.
• Episode 6 provides a more detailed discussion of the statistical web analysis of the replication and comparison of methods experimental results.
• Episode 7 makes use of error grids to compare different quality goals and requirements that might be applied to determine the acceptability of a HbA1c method.
• Episode 8 discusses how to prepare a Method Decision Chart to help judge the acceptability of performance.
• Finally, in Episode 9, we provide a decision chart to summarize the acceptability of performance for all these methods.

It's an in-depth look at today's methods for an important test. Ad for those of us who are out of school, it's valuable chance to re-educate ourselves about the basic concepts.