Hemoglobin screening in prospective blood donors: comparison of different blood samples and different quantitative methods.

Portable photometers are increasingly used for hemoglobin screening in blood centers. In a total of 500 unselected prospective blood donors, venous hemoglobin concentrations were measured using a hematology analyzer, and fingerstick hemoglobin concentrations were measured on both a HemoCue B and a Biotest hemoglobin photometer. In 100 of the donors, earstick hemoglobin levels were also measured on the HemoCue system. The mean hemoglobin levels in the fingerstick samples were slightly higher than those in the venous samples. The deviation exceeded the limit of +/-10g l(-1) in 9% of samples tested by HemoCue and in 20% of those investigated by Biotest. The use of earstick samples led to considerable overestimation of the actual hemoglobin concentration.