If performance goals were decided rationally

November 25, 2011

One of the key questions asked for a diagnostic assay is “is the performance good enough?” This question takes on forms such as: what should the performance goals be? How should they be evaluated? From a regulator’s point of view, there are two decisions that can be made:

Accept the assay – with the risk that patients may be harmed due to assay error
Reject the assay – with the risk that patients may be harmed due to the lack of information that would have been obtained by the assay

Now for any good assay, patients harmed from assay error is always extremely low (e.g., self justifying because it’s a good assay).

And a good assay provides important information to a clinician (e.g., self justifying because it’s a good assay). This also means that the lack of information from a rejected assay would likely cause great harm.

Hence the rational decision is always to approve an assay. Why doesn’t the FDA always approve assays? Perhaps because assays that harm patients are like a plane crash and no one likes plane crashes.

Good and Bad N Numbers

November 7, 2011

Small planes are identified by their tail numbers which in the US are “N” numbers. IMHO, there are good and bad N numbers with the good N numbers being easy to say and the bad N numbers being tongue twisters. I fly two planes N13151 and N2081S (Cessna two zero eight one Sierra) or (Skyhawk two zero eight one Sierra). I have trouble with this N number and stumble over it all the time. Talking to others, they have trouble with certain N numbers as well. This included some air traffic controllers during a recent visit to a control tower – they told me the N numbers that give them trouble.

New Publications

November 4, 2011

My publications come in bunches. These three were just published.

Jan S. Krouwer: A Widespread Myth About Point-of-Care Devices Point of Care: The Journal of Near-Patient Testing & Technology 2011;10:146-147.

Jan S. Krouwer: Analysis of the Performance of the OneTouch SelectSimple Blood Glucose Monitoring System: Why Ease of Use Studies Need to Be Part of Accuracy Studies. Journal of Diabetes Science and Technology, 2011;5:610-611.

Jan S. Krouwer: Evaluation of the Analytical Performance of the Coulometry-Based Optium Omega Blood Glucose Meter: What Do Such Evaluations Show? Journal of Diabetes Science and Technology, 2011;5:618-620.

Additionally, I was interviewed for an article about risk management in Clinical Laboraotry News: http://www.aacc.org/publications/cln/2011/november/Pages/ANewApproachtoQualityControl.aspx?