Unused Samples from Clinical Blood Draws as a Resource for Maximizing Research Samples while Mitigating Iatrogenic...

Translational research driven by large-scale biological testing requires significant volumes of blood for research testing. However, blood is also required for clinical management of research subjects, which must take priority. Paradoxically, much of the blood drawn for clinical management goes unused. Here, we present our approach for retrieving unused blood samples collected for clinical management and recycling them for research purposes.

Clinical Blood samples were collected for 60 days during a 61-day xenotransplantation experiment in a brain-dead decedent. Twice weekly, research staff went to the chemistry and hematology laboratories and collected stored blood, serum, and plasma samples that were >12 hours old. Sample collection and storage before retrieval was per standard clinical protocols. Samples were de-identified and relabeled and brought to a central biorepository for processing and storage. The quantity of plasma, serum, red blood cells (RBCs), and peripheral blood mononuclear cells (PBMCs) collected from clinical labs and bespoke research blood draws were compared.

Unused blood from clinical samples yielded a minimum of 6.0 ml per day of plasma, representing 62% of all plasma obtained. Serum was only recoverable on 13 days (22%), with a mean 2.3 ml collected on those days, representing 8% of all serum obtained. PBMCs were only recoverable on six days (10%).

Overdrawn clinical laboratory samples represent an untapped resource of blood samples for research and can help augment samples collected explicitly for research purposes. With careful planning, this represents an opportunity to minimize iatrogenic blood loss in clinical-translational research.