Desmopressin infusion improves the in vitro platelet dysfunction induced by l-aspirin. Ten healthy volunteers received DDAVP (0.3 μg/kg) over 30 minutes. l-aspirin (50 mg/L) (▴) was added in vitro to blood samples before and after DDAVP infusion. Horizontal dashed lines show the upper and lower limits of normal CEPI-CT and CADP-CT values. Data are presented as mean ± SEM. ^*P < .05, ^**P < .01, and ^***P = .005 versus baseline. DDAVP increased von Willebrand ristocetin cofactor activity (VWF:RCo) levels (top) and thereby shortened both CEPI-CT (citrated blood; middle) and CADP-CT (lepirudinised blood; bottom). DDAVP decreased the aspirin-induced inhibition of platelet function (middle; ▴) with a normalization at 30 minutes and a persistent response for 8 hours.