Fingerstick blood samples in platelet donor screening: reliability and impact on predict yield programs.
Although widely used, the reliability of fingerstick platelet counts for determining donor eligibility and for use with plateletpheresis predict yield programs has not been established. We compared platelet counts obtained from fingerstick vs. venous samples in several aspects of apheresis platelet collection. Analysis of 25 paired fingerstick and venous predonation samples demonstrated a poor correlation between platelet counts (r2 = .43), with fingerstick counts having a 20% lower mean value (P < .05). The effect of using fingerstick vs. venous predonation platelet counts with apheresis instrument predict yield calculations to obtain target yields was determined. Mean yields collected using fingerstick/predict yield were 12% (Fenwal CS3000 PLUS) and 15% (Haemonetics MCS+) higher than venous/predict yield units (P < .05). The coefficients of variation (CV) of fingerstick/predict yield and venous/predict yield collections were comparable (15% vs. 14% [CS3000] and 23% vs. 21% [MCS+], respectively), indicating that possible differences in accuracy between fingerstick and venous platelet counts had little effect on the variability of predict yield collections. A retrospective analysis of the CV of 100 fingerstick/predict yield units vs. 100 units collected by processing standard volumes showed no difference: 22% vs. 20% (F = 0.99, CS3000), and 22% vs. 24% (F = 0.89, MCS+), respectively. We conclude that fingerstick platelet counts are systematically lower and correlate poorly with venous counts, though their use seldom results in false disqualification of donors. We also conclude that fingerstick count/predict yield collections do not produce more consistent yields of platelets than standard volume collections.
Randels
M J
MJ
College of Medicine, University of Iowa, Iowa City, USA.
Strauss
R G
RG
Raife
T J
TJ
D001782:Blood Donors; D001800:Blood Specimen Collection / Q000379:methods*; D006801:Humans; D010976:Platelet Count; D017713:Platelet Transfusion