By rray, 11 December, 2014 C:Evidence - very limited populations evaluated, only consensus opinion, case studies, or SOC
By rray, 11 December, 2014 B:Evidence - limited populations evaluated, single RCT or nonrandomized studies
By rray, 11 December, 2014 A:Evidence - multiple populations evaluated, multiple RCTs or meta-analyses
By rray, 11 December, 2014 N:No recommendation for or against (insufficient/unclear/conflicting evidence)