Statistical analysis of inappropriate results from current Hb screening methods for blood donors.
BACKGROUND
The objective was to apply statistical analysis to the false passes and fails that occur with the primary and secondary Hb-screening methods used at blood-donor sessions.


METHODS
Venous samples from 1513 potential donors who had undergone primary CuSO4 screening using capillary blood (Hb cut-offs: women, 125 g/L; men, 135 g/L) were tested at the session by a secondary method (HemoCue; cut-offs: women, 120 g/L; men, 130 g/L) and again at the base laboratory using another system (Beckman Coulter General S system), which generated the "true" Hb value.


RESULTS
False-pass and -fail rates for women and men, respectively, were 11.2 and 6.3 percent (women) and 5.2 and 1.8 percent (men) for CuSO4; 1.9 and 3.7 percent (women) and 1.5 and 0.4 percent (men) for HemoCue; and 2.7 and 2.4 percent (women) and 1.8 and 0.2 percent (men) for a combined procedure that mimicked current practice of only testing CuSO4 fails by HemoCue.


CONCLUSIONS
CuSO4 Hb screening gives large numbers of false passes, particularly in women. Using venous samples, the majority correctly pass at the lower HemoCue cut-offs. The current dual-testing policy appears convenient for donor sessions, but because small percentages of false passes and fails represent large numbers of donors, every effort should be made to improve the accuracy of Hb screening.
James
Virge
V
National Blood Service, Trent Center, Sheffield, UK. virge.james@nbs.nhs.uk
Jones
Keith F
KF
Turner
Elizabeth M
EM
Sokol
Robert J
RJ
D001782:Blood Donors; D002196:Capillaries; D019327:Copper Sulfate; D005188:False Negative Reactions; D005189:False Positive Reactions; D005260:Female; D006452:Hemoglobinometry / Q000379:methods; D006454:Hemoglobins / Q000032:analysis*; D006801:Humans; D008297:Male; D014680:Veins
D006454:Hemoglobins; D019327:Copper Sulfate