Dear all

what is the reson that the platelet concentrate container should be left stationary ,with the label side down , at room temperature for 1 hour after the heavy spin?

the plts have all "adhered" together following the spin. The 1 hr at room temp allows them to "relax" and go back into solution following the processing steps.

Hi,

Platelets are activated in two steps. The first is that they aggregate. The aggregation phase can be reversed if the platelets are not pushed to the second stage of activation. The the forces of centrifugation cause the platelets to be activated to the aggregation stage. Microscopically the platelets go from a discoid shape to a spherical shape. By letting the platelets "rest" you permit the reversal the aggregation process and the platelets assume the discoid shape. Should the activation process continue, the platelets degranulate and will no longer function well to produce hemostasis.

The reason for the label down probably stems from the production of platelets from whole blood. The label occupies a lot of real estate on the bag, and the label is not. The bags are gas permeable permitting the "release" of CO2, the product of glycolysis, out of the bag and for O2 (which is necessary for glycolysis) to be absorbed into the platelet. Having the bag label down optimizes the surface area available for this to occur while the platelet is "resting". This permits adequate gas exchange permitting glycolysis and maintaining the Ph of the plasma.

David Saikin ,Kip Kuttner

thank you so much for making this very clear.