Accuracy of predonation Hct sampling affects donor safety, eligibility, and deferral rates.
BACKGROUND
Safe blood donation depends upon reliable predonation Hct screening. Earstick (ES) capillary samples are frequently used, but they may not be accurate.


METHODS
Predonation ES and fingerstick (FS) and postdonation venous Hct results were compared in 1960 whole-blood and 210 apheresis donors. The validity of using postdonation venous samples to evaluate predonation ES and FS Hct was assessed in 20 whole-blood donors. The impact of Hct screening method on donor Hct deferrals was examined during periods when either ES or FS sampling was used exclusively.


RESULTS
All donors were eligible to donate on the basis of a predonation capillary Hct of > or = 38 percent. In venous samples obtained immediately after donation, 36 percent of whole-blood donors had a Hct <38 percent. With correction for a decrease of approximately 2 Hct units during donation, 20 percent of these donors had a predonation Hct <38 percent. The lowest venous Hct was 23.1 percent. FS samples showed better correlation with venous Hct. Hct discrepancies were similar for apheresis donors. Hct deferrals were significantly higher with FS sampling, especially among women.


CONCLUSIONS
Hct determinations from ES samples overestimate venous Hct. Fingerstick samples are more sensitive in detecting anemia. The accuracy of predonation Hct sampling has implications for donor safety, eligibility, and deferral rates.
American Red Cross Blood Services, Northern Ohio Region, Cleveland, Ohio, and the American Red Cross Blood Services, North Central Region, St. Paul, Minnesota 55107, USA.
E M
EM
Wood
D M
DM
Kim
J P
JP
Miller
D001781:Blood Component Removal; D001782:Blood Donors; D002196:Capillaries; D019327:Copper Sulfate; D004431:Ear, External / Q000098:blood supply; D005260:Female; D005385:Fingers / Q000098:blood supply; D006400:Hematocrit; D006403:Hematologic Tests; D006801:Humans; D008297:Male; D010560:Personnel Selection / Q000379:methods*; D012449:Safety; D014680:Veins
D019327:Copper Sulfate