Servicio de Análisis Clínicos, Hospital San Agustín, Avilés, Principado de Asturias, Spain.
Clin Chem Lab Med. 2010;48(1):99-104. doi: 10.1515/CCLM.2010.008.
Biological variation data for free plasma amino acids are lacking from the more comprehensive databases. Therefore, we determined the intra- and inter-individual components of variation in healthy subjects. These data were used to define desirable goals for imprecision, bias and total error, indices of individuality and reference change values.
Plasma samples were collected from 11 volunteers at weekly intervals over 5 weeks. Free plasma amino acids were analyzed by reversed-phase HPLC and analytical and biological variation data were derived using ANOVA.
Intra-individual coefficients of variation ranged from 9.5% to 46.4%, with lower values among the essential amino acids. The mean inter-individual coefficient of variation was 46.6% and was higher than intra-individual values for all amino acids. Thus, indices of individuality were below 0.8. Reference change values ranged from 30.9% to 128.4% and total error values ranged from 15.2% to 61.0%.
Plasma amino acids exhibit relatively low intra-individual coefficients of variation, with essential amino acids showing tighter homeostatic control. Analytical quality goals can be reasonably achieved with current methods. Reference intervals are of limited value in the detection of unusual results in an individual. Therefore, comparison of serial results by means of the reference change values is recommended.
更全面的数据库中缺乏游离血浆氨基酸的生物学变异数据。因此，我们确定了健康受试者个体内和个体间的变异组成部分。这些数据用于定义不精密度、偏差和总误差、个体指数和参考变化值的理想目标。
在 5 周的时间内，每周从 11 名志愿者采集血浆样本。通过反相高效液相色谱法分析游离血浆氨基酸，并使用方差分析得出分析和生物学变异数据。
个体内变异系数范围为 9.5%至 46.4%，必需氨基酸的变异系数较低。个体间平均变异系数为 46.6%，所有氨基酸的个体间变异系数均高于个体内变异系数。因此，个体指数均低于 0.8。参考变化值范围为 30.9%至 128.4%，总误差值范围为 15.2%至 61.0%。
血浆氨基酸的个体内变异系数相对较低，必需氨基酸显示出更严格的体内平衡控制。目前的方法可以合理地实现分析质量目标。参考区间在个体中检测异常结果的价值有限。因此，建议通过参考变化值比较连续结果。
