Re: Do we need BQL?

Date: Tue, 03 Aug 1999 08:09:44 -0700 From: LSheiner <lewis@c255.ucsf.edu> Subject: Re: Do we need BQL? Ah, a breath of science instead of simply speculation. Indeed, the censoring that BQL represents is self-induced, and probably stems from the fact that labs are reluctant to state a number when the (%) uncertainty in that number is very high. We now know how to deal with varying degrees of uncertainty, and are, in fact, losing information by censoring our very low observations. A key point here is that we use the model for the "signal" to determine the magnitude of the noise, so we are not left with only the libertarian's calibration curves and daily controls; we examine internal evidence and construct a variance model that is compatible with our notion of the underlying process. In so doing, we would be aided by getting an honest report from the lab on what it's machines said, rather than an arbitrarily censored one. Good point. LBS. PS. Why is "limit of detection" meaningful? Is it not simply the lowest value reliably distinguishable from zero? Doesn't the error model cover this as part of its continuum? -- Lewis B Sheiner, MD Professor: Lab. Med., Biopharm. Sci., Med. Box 0626 voice: 415 476 1965 UCSF, SF, CA fax: 415 476 2796 94143-0626 email: lewis@c255.ucsf.edu