- Citrate reaction: a neuromuscular hyperactivity related to reduced ionized calcium levels. Infusion of citrate anticoagulant during apheresis binds calcium causing a fall in ionised calcium levels, leading to neuromuscular hyperactivity. Operator error with mix up of saline and citrate bags may occur with some apheresis equipment leading to rapid citrate infusion. Signs and symptoms include numbness or tingling of lips or fingers, feelings of vibrations, metallic taste, chills, shivering, light-headedness, feeling of tightness, muscle twitching, rapid or slow pulse and/or shortness of breath. Symptoms may progress to carpopedal spasms and vomiting; if untreated, symptoms may progress to generalised muscle contractions (tetany) and severe cardiac arrhythmias, including cardiac arrest.

- Haemolysis: Donor red cells may be damaged during apheresis procedures, releasing haemoglobin. Equipment malfunctioning valves, kinks or obstruction of tubing, incorrect installation of equipment, or other equipment failures affecting the extracorporeal circuit, most commonly cause this. In addition, incompatible replacement fluids, such as dextrose D5W, may be used in error. The presence of hemoglobin in the circulation is recognized by pink or red plasma, blood in lines or a dark appearing filter. The donor may notice pink or red urine after collection.

- Air embolism: Air bubble introduced into the donor’s circulation. Air may enter into the lines due to incomplete priming of lines, as a result of a machine malfunction or defective collection kits or through incorrect manipulation by staff. Air in the donor’s pulmonary circulation may occlude the pulmonary arteries in the lung and cause cardiopulmonary symptoms. Air may pass to the arterial circulation through an atrial septal defect, and reduce blood flow to the brain. This very rare event may be recognized by a bubbling sound or feeling at the venipuncture site accompanied by cough, dyspnea, apprehension, sweating, chest pain, confusion, tachycardia, hypotension, nausea and vomiting.