Table 1. Criteria for the four-tiered CCC-CNS levels of evidence system.

analytical performance	A Robust confirmation of sufficiently high analytical performance by one or more adequately designed and published round robin/ring trials
	B Sufficient evidence for high analytical performance from adequately designed published investigations
	C Promising analytical performance from published investigations
	D Unclear analytical performance based on published single laboratory experience, inconsistent results between different studies, expert opinion
clinical performance (prognostic/predictive)	A Robust confirmation of sufficiently high clinical performance by one or more adequately designed and published prospective studies
	B Sufficient evidence for high clinical performance from adequately designed published investigations
	C Promising clinical performance from published investigations
	D Unclear clinical performance based on published single center experience, inconsistent results between different studies, expert opinion
clinical utility	Both ≥ B = sufficient evidence for routine clinical use At least one < B = insufficient evidence for routine clinical use