The amount of a ribonucleoside-diphosphate reductase subunit M2 B (human) when measured in cerebrospinal fluid. The trait is level of ribonucleoside-diphosphate reductase subunit M2 B (human) in cerebrospinal fluid (OBA_2059494). Also known as: cerebrospinal fluid ribonucleoside-diphosphate reductase subunit M2 B (human) amount.