Several years ago, we began a process of evaluating novel risk factors for cardiovascular disease and identified three critical criteria. First, is there an assay that has standardized conditions, so that if we measure it with one clinical chemistry setting, we get the same value as we do in another? This has been a major issue for lipoprotein(a), a unique marker of atherothrombosis that unfortunately can be very difficult to measure and still has not been standardized at a clinical level. The second criterion is the requirement for a consistent series of prospective epidemiologic studies. Prospective studies are those that ascertain the abnormality of interest before the onset of the first heart attack or stroke, and we would like those data to be highly internally consistent. This has been an issue for homocysteine evaluation, for which many prospective epidemiologic studies have been positive but others have been less promising. But the third and most important clinical criterion is the additive value of the new marker over and above standard cholesterol screening. This has been the issue of interest for the inflammatory markers, particularly fibrinogen and hs-CRP, because in fact these markers do appear to add to the predictive value of standard lipid evaluation.

Reference:
Ridker PM. Evaluating novel cardiovascular risk factors: can we better predict heart attacks? Ann Intern Med 1999;130:933-937.
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