Decreased ionized calcium during therapeutic plasma exchange pheresis and platelet pheresis.

Marked reductions in ionized calcium were observed in normal donors undergoing platelet pheresis using acid-citrate dextrose formula A (ACD)-A) anticoagulant, and in patients undergoing therapeutic plasma exchange pheresis using citrate phosphate dextrose (CPD)-ABO compatible plasma. Donors showed a greater tendency to symptoms of hypocalcemia, although patients receiving CPD plasma demonstrated lower values of ionized calcium. It is suggested that there may be important differences in the availability of calcium from plasma containing these two anticoagulants.