Use of sentinel sites for daily monitoring of the US blood supply.

BACKGROUND: This report describes the first year of a government-sponsored program that uses daily reports from 29 sentinel sites to monitor the capacity of the US blood supply to meet demand. STUDY DESIGN AND METHODS: From August 15, 2001, to August 14, 2002, 29 sentinel sites provided daily reports of the number of units of RBCs in inventory, transfused, exported, and outdated by ABO and Rh, and platelets by random or apheresis donor. Days supply of each component category was calculated as the number of units in inventory reported on a day divided by the sum of units transfused, exported, and outdated on that day. Sites also provided daily responses to questions about threatened or actual shortages. RESULTS: The median of the days supply of RBCs at the 26 hospital transfusion services was 7.2 days. However, median days supply varied substantially by site and by day of the week. A+, O+, and O- units accounted for 30, 35, and 12 percent of total inventory and were maintained at a median supply of 7.4, 6.4, and 9.5 days, respectively. Reports of threatened RBC shortages peaked in early January 2002 and again in early July 2002. The July 2002 peak was about twice the January 2002 peak. Inventories at community-based centers were similar to those at hospital transfusion services. Hospitals maintained only a 1-day supply of platelets. Eight percent of random and 4 percent of apheresis platelets were outdated. There were 20 reports that surgery had to be postponed or canceled because platelets were unavailable. CONCLUSIONS: Inventories of RBCs maintained at the participating sites were sufficient, with only one brief exception, to meet local demand during the first year of this monitoring program. The weekly rate of threatened shortage reports was more sensitive than days inventory as a predictor of actual shortages of RBCs. Unlike RBCs, platelet days supply, reports of threatened or actual platelet shortages, and platelet outdate rates did not vary seasonally.