TABLE 4.

Median percentage difference in allogeneic RBC units transfused in 2013 and 2015 from matched hospitals, stratified by surgical volume

Surgical volume: Surgeries per year	No.*	Median (mean) 2015 allogeneic RBC units*	Median % difference†	IQR of % difference†
100–999	106	397 (561)	−22.4	38.5
1,000–1,399	79	1,271 (1,426)	−15.8	22.4
1,400–2,399	108	1,993 (2,248)	−13.0	26.5
2,400–4,999	155	3,791 (4,056)	−11.8	18.5
5,000–7,999	72	6,094 (7,069)	−10.3	14.4
≥8,000	74	13,096 (15,442)	−3.9	20.8
Total	594	2,796 (4,538)	−12.2	23.8

^*Based on matched facilities reporting allogeneic red blood cells in both 2013 and 2015 National Blood Collection and Utilization Surveys.

^†The percentage difference is calculated as 100*(2015–2013)/2013.

IQR=interquartile range (75th to 25th percentile).