HOCl-LDL rapidly potentiates platelet aggregation in the presence of low levels of ADP. Washed platelets were exposed under low shear to ox-LDL alone (20 μg/mL, □), ADP alone (1 μM, ○), and dual addition of HOCl-LDL and ADP (▴). Aggregation was assessed by light scattering (A) and single-particle counting (B). Platelet singlet counts were taken at 0, 5, 30 seconds, 4 minutes, and 8 minutes after agonist challenge. ^*P < .05 (n = 5).