A novel true volumetric method for the determination of residual leucocytes in blood components.
OBJECTIVE
Accurate determination of residual leucocytes [white blood cells (WBC)] in blood components is of high clinical importance. To date, several labour-intensive, time-consuming or expensive techniques have been used for this purpose.


METHODS
A method for the determination of residual WBC is described using a novel low-cost flow-cytometric cell counter and analyser (CCA). The DNA in WBC was stained using 4'-6-diamidino-2-phenylindole (DAPI) and WBC were automatically analysed by true volumetric counting of 200-microl samples (prepared from a 20-microl undiluted sample).


RESULTS
Dilution experiments over a range of 0.5-50 WBC/microl showed a linearity of r = 0.998. The detection limit of this method was 0.83 WBC/microl of red blood cell concentrate (RCC) and 0.67 WBC/microl of platelet concentrate (PC), with an accuracy of 95.5%.


CONCLUSIONS
Residual WBC (< 1 WBC/microl) can be accurately counted using the CCA within 2 min and at a total cost of less than euro 1 per sample.
Cassens
U
U
Institute for Transfusion Medicine/Department for Transplantation Immunology, University Hospital Münster, Germany. cassenu@uni-muenster.de
Greve
B
B
Tapernon
K
K
Nave
B
B
Severin
E
E
Sibrowski
W
W
Göhde
W
W
D016913:Blood Component Transfusion; D003363:Cost Control; D005434:Flow Cytometry / Q000379:methods*; D005470:Fluorometry; D006801:Humans; D007958:Leukocyte Count; D007962:Leukocytes