Washing platelets in neutral, calcium-free, Ringer's acetate.
BACKGROUND
Washed platelets (PLTs) are occasionally requested for patients with histories of allergic or anaphylactic reactions. Washing methods and conditions result in the loss of PLT number and function. Short postwash storage times occasionally conflict with other patient activities and result in the wastage of washed products. Better washing procedures are a start to longer postwash hold times.


METHODS
Twenty-six units of just-outdated 6- or 7-day-old apheresis PLT concentrates were sampled; washed in neutral, calcium-free, Ringer's acetate (NRA); allowed to recover for 0.5 hour; and resampled. PLTs were counted, subjected to transmission electron microscopy, diluted with either equal-volume NRA (prewash) or autologous plasma (postwash), and subjected to thromboelastography. Pre- and postwash products were compared.


RESULTS
PLT recovery was 71%. Plasma removal was 96%. Electron microscopy PLT morphology was unchanged by washing. Thromboelastography showed a mild decrease in final clot strength after washing that was not related to PLT concentration.


CONCLUSIONS
PLT washing in NRA allows good recovery of PLT numbers and good preservation of function in vitro as assessed by thromboelastography. If performed in a closed-system cell washer, extension of the current 4-hour storage time for washed PLTs should be possible.
Kelley
Walter E
WE
Department of Pathology, University of Maryland School of Medicine, Baltimore, Maryland 21201, USA.
Edelman
Bennett B
BB
Drachenberg
Cinthia B
CB
Hess
John R
JR
D001777:Blood Coagulation; D001792:Blood Platelets / Q000166:cytology* / Q000648:ultrastructure; D001793:Blood Preservation / Q000379:methods*; D002118:Calcium / Q000737:chemistry*; D006801:Humans; D007552:Isotonic Solutions / Q000737:chemistry*; D010976:Platelet Count
D007552:Isotonic Solutions; C028570:Ringer's acetate; D002118:Calcium