Jiao Y, Okumiya T, Saibara T, Tsubosaki E, Matsumura H, Park K, Sugimoto K, Kageoka T, Sasaki M
Department of Clinical Laboratory Medicine, Kochi Medical School, Nankoku Japan.
Clin Biochem. 1998 Mar;31(2):59-65. doi: 10.1016/s0009-9120(97)00164-1.
To establish and estimate an enzymatic measurement of creatine in erythrocytes as an index of the erythrocyte life time.
The measurement of creatine in erythrocytes was performed using an enzymatic assay kit that was developed for serum and urine creatine. An erythrocyte sample was subjected to creatine measurement after hemolysis and deproteinization. Performance of the method for creatine measurement in erythrocytes was estimated. Effects of age and gender on the creatine content of erythrocytes were also estimated in 305 normal subjects.
The method showed within-run CVs varying from 0.7 to 1.0% (n = 20), and between-day CVs from 1.3 to 1.7% (15 days). Good linearity was observed at least up to 1000 mumol/L as creatine value in hemolyzed sample. The analytical recovery was calculated to be 98.1 +/- 1.3% on average. No considerable interference by various substances, including guanidino compounds and amino acids, with the assay was observed. Excellent correlation was observed between the present method and high performance liquid chromatography. With the unit of mumol/g Hb: slope, 1.034 +/- 0.003 (mean +/- SD); intercept, -0.059 +/- 0.012 (mean +/- SD); correlation coefficient, 0.9996; and Sy.x, 0.069. With the unit of mumol/L RBC: slope, 1.033 +/- 0.003 (mean +/- SD); intercept, -18.23 +/- 3.55 (mean +/- SD); correlation coefficient 0.9996; and Sy.x, 20.40. A significant increase in erythrocyte creatine was observed in females aged 11- to 50 years old as compared with males in the corresponding age bracket, however, a gender difference was not observed in other age bracket. This finding suggests the possibility of a slight decrease in the erythrocyte life time due to menstruation in females.
This study showed that the present method is favorable for quantifying erythrocyte creatine, and has analytical characteristics suitable for routine work in clinical laboratories.
建立并评估一种测定红细胞中肌酸的酶法，以此作为红细胞寿命的指标。
使用一种为血清和尿肌酸开发的酶分析试剂盒来测定红细胞中的肌酸。红细胞样本经溶血和去蛋白处理后进行肌酸测定。评估该方法测定红细胞中肌酸的性能。还在305名正常受试者中评估了年龄和性别对红细胞肌酸含量的影响。
该方法批内变异系数（CV）为0.7%至1.0%（n = 20），批间变异系数为1.3%至1.7%（15天）。在溶血样本中，肌酸值至少在1000 μmol/L时呈现良好的线性关系。分析回收率平均计算为98.1±1.3%。未观察到包括胍基化合物和氨基酸在内的各种物质对该测定有明显干扰。该方法与高效液相色谱法之间观察到极好的相关性。以μmol/g Hb为单位：斜率为1.034±0.003（均值±标准差）；截距为 -0.059±0.012（均值±标准差）；相关系数为0.9996；标准估计误差（Sy.x）为0.069。以μmol/L RBC为单位：斜率为1.033±0.003（均值±标准差）；截距为 -18.23±3.55（均值±标准差）；相关系数为0.9996；标准估计误差（Sy.x）为20.40。与相应年龄组的男性相比，11至50岁女性的红细胞肌酸显著增加，然而，在其他年龄组未观察到性别差异。这一发现提示女性可能因月经导致红细胞寿命略有缩短。
本研究表明，该方法有利于定量红细胞肌酸，且具有适合临床实验室常规工作的分析特性。
