Background:Adverse effects due to apheresis are unusual. The most common apheresis-specific reaction is hypocalcemia due to citrate anticoagulation and induces ionized hypocalcemia and hypomagnesemia by chelating effect during the plateletpheresis; generally transient and self-limiting but has the potential of severely injuring donor. We have investigated total calcium (tCa++) and magnesium (tMg++) levels in sixty healthy plateletpheresis donors at different intervals during the procedure and 30 min post-procedure.Materials and Methods:A total of 60 procedures were performed on healthy donors. Blood samples were obtained from sterile diversion pouch placed on apheresis circuit. 5 ml sample in plain vials was obtained at different intervals during each procedure and 30 min after the end of the procedure. Samples were used for measurement of tCa++ and tMg++ levels.Results:There is continuous decrease in mean tCa++ from baseline levels (9.83 ± 0.64 mg/dl) till end of procedure (8.33 ± 0.78 mg/dl), but after 30 min, levels again reached near their respective baseline values (9.42 ± 0.54 mg/dl). Similarly, mean tMg++ fell from baseline levels (2.36 ± 0.3 mg/dl) till the end of procedure (1.39 ± 0.40 mg/dl). After 30 min, levels were again increased, their respective baseline values (2.25 ± 0.25 mg/dl).Conclusion:There is continuous, gradual, and significant fall (P < 0.05) in mean tCa++ and mean tMg++ from baseline levels to till the end of procedure but after 30 min of completion of procedure, levels again reached near their respective baseline values.