Medical guidelines may not always be compatible with laboratory practice

 Michel R. Langlois,  MD, PhD

Dept. of Laboratory Medicine, AZ St-Jan Bruges, and University of Ghent, Belgium.

EFLM WG-Guidelines.

Medical guidelines on the use of in vitro diagnostic biomarkers are usually based on population studies that assessed the diagnostic performance of the biomarker (with a certain analytical method). However, these guidelines and the recommended cut-off values of the biomarker may not always be universally applicable, e.g., due to lack of standardization and between-method/between-laboratory variability. Often the recommended biomarkers are not completely validated according to essential criteria for medical use: analytical performance, clinical (diagnostic) performance, clinical- and cost-effectiveness. In the example of medical guidelines for cardiovascular disease prevention,  LDL-cholesterol targeted strategies are based on population studies using the older precipitation methods and, therefore,  not validated for use of the contemporary direct (homogeneous) assays.