Abstract: Objective To understand change of serum magnesium during plateletpheresis and the effect of donation frequency on serum calcium, magnesium and parathyroid hormone (PTH) in regular plateletpheresis donors. Methods A total of 29 plateletpheresis donors were divided into two groups based on their donation frequency: high frequency (n=16,>12 times per year), low frequency (n=13, ≤12 times per year). Serum levels of calcium, magnesium and PTH in donors at 0 min, 30 min, 60 min, 90 min of plateletpheresis were measured. The differences of the three markers between groups was analyzed by analysis of variance of repeated measurement data. Results The serum calcium（mmol/L）of donors in low frequency group and high frequency group at 0 min, 30 min, 60 min, 90 min of plateletpheresis were 2.41±0.23 vs. 2.40±0.13、2.17±0.22vs. 2.26±0.11、2.20±0.24 vs. 2.27±0.14、2.21±0.22 vs. 2.28±0.18, respectively, and all of which decreased compared to the beginning of plateletpheresis, and the decreased levels was at 30 minutes, 60 minutes, and 90 minutes after starting plateletpheresis. Serum magnesium (mmol/L) were 0.76±0.18 vs. 0.75±0.21、0.69±0.21vs. 0.71 ± 0.21、0.70±0.19 vs. 0.72±0.19、0.71±0.20 vs. 0.73±0.18, respectively. The change trend was similar to that of serum calcium. Serum PTH (pg/mL) were 40.32±17.24 vs. 60.35±58.80、138.87±63.55 vs. 190.43±64.85、129.14±65.70 vs. 162.68±47.19、89.00±63.85 vs. 122.22±57.90, respectively, and all of which increased compared to the beginning of plateletpheresis. The increased levels was at 30 minutes, 60 minutes, and 90 minutes after starting plateletpheresis. Only the PTH levels between the two groups were 138.87±63.55 vs. 190.43±64.85 at 30 min of plateletpheresis (P<0.05). Conclusions erum magnesium decreased, and PTH in donors with lower donation frequency significantly increased during plateletpheresis, which should arouse more attention of blood collection and supply institutions.

Key words: Plateletpheresis, Donation frequency, Parathyroid hormone, Serum calcium, Serum magnesium