The Office Measurement of Cholesterol

To the Editor. —  I read with interest the article entitled "A Clinician's Guide to the Office Measurement of Cholesterol" by Mr Burke and Dr Fischer.¹ A number of important aspects of office analyzers were discussed, and I would like to offer some comments.First, comparisons were done in part using blood treated with edetic acid. This substance is not the one of choice for the Reflotron cholesterol method.²Second, the analytic range is defined as the "range for which the test method accurately measures cholesterol." This definition means that the method has good linearity in that range (otherwise it cannot be accurate). In the discussion of linearity, it is stated that "commonly there is less precision and an increased bias at the extreme of the analytic range." This last sentence does not square with the definition of the analytic range.Third, in the discussion concerning precision it