Flocculation activity of FeCl₃. (A) The concentration-dependent ability of FeCl₃ to aggregate blood components can be seen microscopically. At mid-range concentrations of FeCl₃, amorphous iron hydroxide precipitates can be seen. Platelets (green: CD41); fibrinogen (red). (B) Light scattering of PRP (left) when exposed to a range of FeCl₃, AlCl₃, and CrCl₃ concentrations. Values are expressed as fold increase over control PRP, where increased scatter corresponds to increased aggregation. Light scattering of PPP (right) exposed to a range of FeCl₃, AlCl₃, and CrCl₃ concentrations. Values are expressed as fold increase over control PPP. All scale bars represent 50 μm; N = 3.