Remnant Blood Quantification: Informing the Definition of Minimal Risk in Clinical Research

Guidelines from the Office for Human Research Protections regarding categories of research that institutional review boards (IRBs) may review through expedited procedures limit the volume of blood that can be obtained from research participants for minimal risk research purposes. As defined by the Common Rule, minimal risk research is research in which the probability and magnitude of harm or discomfort anticipated are not greater than the probability and magnitude of harm or discomfort encountered from routine clinical tests. For this study, we considered the volume of remnant blood following routine clinical tests in light of the current definition of minimal risk in research. Conducted at a single institution, this was a prospective cross-sectional study that evaluated blood draws from 122 patients. The median daily remnant blood volume was 11.6 (interquartile range [IQR]: 12.3, 15.2) ml for all patients and 12.9 (IQR: 13.1, 16.9) ml for patients admitted to the intensive care unit. Our findings regarding daily remnant blood volume suggest that the currently allowable blood-volume limits to qualify for expedited review or to qualify as not more than minimal risk research involving blood draws from nonhealthy adults are less than what patients experience in routine medical testing. These findings support permitting an increase in the allowable blood-volume limits to meet the regulatory definition of minimal risk research for obtaining expedited IRB review of studies in which blood samples will be collected.