Table C.2.

Levels of Evidence – Diagnosis
Level 1 – Studies of Test Accuracy Among Consecutive patients	Level 1.a – Systematic review of studies of test accuracy among consecutive patients
	Level 1.b – Study of test accuracy among consecutive patients
Level 2 – Studies of Test Accuracy Among Non-Consecutive Patients	Level 2.a – Systematic review of studies of test accuracy among non-consecutive patients
	Level 2.b – Study of test accuracy among non-consecutive patients
Level 3 – Diagnostic Case Control Studies	Level 3.a – Systematic review of diagnostic case control studies
	Level 3.b – Diagnostic case-control study
Level 4 – Diagnostic Yield Studies	Level 4.a – Systematic review of diagnostic yield studies
	Level 4.b – Individual diagnostic yield study
Level 5 – Expert Opinion and Bench Research	Level 5.a – Systematic review of expert opinion
	Level 5.b – Expert consensus
	Level 5.c – Bench research/single expert opinion