Sigma Metric Analysis
In a 2009 issue of Annals of Clinical Biochemistry, a study takes on two Point-of-Care HbA1c devices using two different reference methods. Both POC methods are standardized to the IFCC reference system and aligned to DCCT standards via the National Glycohemoglobin Standardization Program (NGSP). Both reference methods are also standardized against the IFCC reference method and traceable to DCCT and NGSP. If everything is standardized and traceable, there can't be any problems, right?
A poster at the IFCC conference applied Sigma-metric analysis to a number of hematology methods, including differential parameters, on the Sysmex xt 1800i. Interestingly, they chose Biologic-based quality requirements, not the usual CLIA goals. We review the data and generate some graphic analysis.
Tight Glycemic Control is one of the latest trends in laboratory medicine - one that requires fast, frequent, and precise testing. A 2008 paper studied four different glucose methods, one POC, 2 blood gas, and one central laboratory hexokinase method. Can you guess which methods performed the best, and what methods were good enough to support TGC?
We take a look at data on a new mid-volume chemistry analyzer, based on data from an abstract at the 2009 AACC/ASCLS/CSCC meeting. If you buy the latest generation of chemistry instruments, does that guarantee you're getting world class methods?
We recently received a set of data for a chemistry analyzer. An analysis of these numbers gives us an eye-opening glimpse of real-world performance. On some tests, there were Sigma-metrics higher than 20! And yet on one test, the Sigma metric was actually below 1.0!! See which tests were good, which ones were great, and which ones were just plain ugly.