Husdan H, Leung M, Oreopoulos D, Rapoport A
Clin Chem. 1977 Sep;23(9):1775-7.
Ca2+ was measured in sera and plasma from 36 normal subjects (18 men 23-57 years old, and 18 women 20-52 years old) with the Space-Stat 20 Ionized Calcium Analyzer. Within-day and between-day precision (CV) for commercial serum-based specimens varied from 0.64-0.96% and 1.1-3.8%, respectively, depending on their mean concentrations. Plasma and serum showed within-day CV's of 1.05 and 0.79%, respectively. The linear regression of serum Ca2+ (y) on plasma Ca2+ (x) was y = 0.63x + 0.45 mmol/litre with a highly significant (P less than 0.001) coefficient of correlation (r) of 0.69. An approximate 5% increase in the mean Ca2+ concentration in serum over that found in plasma is probably due to heparin complexing. No significant sex-related difference was observed for either serum or plasma. The mean Ca2+ concentration of 29 refrigerated specimens tended to decrease in seven days (by 2.3%, not statistically significant). The normal Ca2+ range in serum and plasma (n = 35) was 1.08-1.18 and 1.02-1.14 mmol/litre, respectively.
使用Space-Stat 20离子钙分析仪对36名正常受试者（18名年龄在23至57岁之间的男性和18名年龄在20至52岁之间的女性）的血清和血浆中的Ca2+进行了测量。对于基于商业血清的标本，日内和日间精密度（CV）分别在0.64 - 0.96%和1.1 - 3.8%之间变化，具体取决于它们的平均浓度。血浆和血清的日内CV分别为1.05%和0.79%。血清Ca2+（y）对血浆Ca2+（x）的线性回归方程为y = 0.63x + 0.45 mmol/升，相关系数（r）为0.69，具有高度显著性（P小于0.001）。血清中Ca2+平均浓度比血浆中大约高5%，这可能是由于肝素络合所致。在血清或血浆中均未观察到显著的性别差异。29份冷藏标本的平均Ca2+浓度在7天内有下降趋势（下降2.3%，无统计学意义）。血清和血浆（n = 35）中的正常Ca2+范围分别为1.08 - 1.18 mmol/升和1.02 - 1.14 mmol/升。
