Ontology of Biological Attributes term OBA_2052049 (amount of ribonucleoside-diphosphate reductase subunit M2 B (human) in blood) is the amount of a ribonucleoside-diphosphate reductase subunit M2 B (human) when measured in blood. Also known as: blood ribonucleoside-diphosphate reductase subunit M2 B (human) amount.