血液样本加热灭活对液相色谱-质谱联用法监测丙戊酸血药浓度的影响

Effects of the heat-inactivation of blood samples on blood concentration monitoring of valproic acid by LC-MS

目的:探讨血液样本56℃灭活30 min对液相色谱-质谱联用(LC-MS)法丙戊酸(valproic acid, VPA)治疗药物监测的影响。方法:血浆样本经乙腈蛋白沉淀处理后,采用LC-MS法测定血浆质控品和临床样本灭活前后VPA的浓度。采用Bland-Ahman、Passing-Bablok回归和线性回归分析灭活前、后测定结果的一致性和相关性。结果:VPA 56℃灭活30 min未有明显降解,灭活前后基质效应无明显差异。128例临床样本中,灭活组血药浓度(四分位数)为82.5(64.6~102.4)μg·mL^(-1),未灭活组血药浓度为83.0(62.4~99.3)μg·mL^(-1),灭活前后VPA血药浓度差异无统计学意义(P>0.05)。经Bland-Altman分析,95%CI=(0.405,2.408),95.4%(6/128)的差值都位于一致性界限内,提示灭活前后测定值一致性良好。Passing–Bablok回归方程为VPA_(灭活)=1.016×VPA_(非灭活)-0.017 2,截距95%CI=(-2.254,2.183),斜率95%CI=(0.979,1.050)。Spearman相关系数为0.986 1(P<0.01),表明灭活前、后VPA血浆浓度值具有良好的相关性。结论:56℃30 min灭活结合蛋白沉淀处理血浆样本对LC-MS法测定VPA血浆浓度无明显影响,可用于VPA常规治疗药物监测。

OBJECTIVE To investigate the effects of inactivation at 56 ℃ for 30 min on therapeutic drug monitoring(TDM) of valproic acid(VPA) by LC-MS.METHODS After protein precipitation by acetonitrile, inactivated and non-inactivated VPA concentrations in quality control and clinical samples were quantified by LC-MS. Furthermore, the difference, consistency and correlation of the results were evaluated and analyzed by Bland-Altman, Passing-Bablok regression and linear regression.RESULTS There was no significant degradation of VPA after inactivation at 56 ℃ for 30 min, and the matrix effect had no significant difference when compared with non-inactivated VPA concentration. In 128 cases of clinical samples, the VPA blood concentrations of the inactivated and non-inactivated groups were 82.5(64.6-102.4) μg·mL^(-1) and 83.0(62.4-99.3) μg·mL^(-1), respectively, which were not statistically significant(P>0.05). Bland-Altman analysis showed that the consistency between the measurements of inactivated and non-inactivated samples was good with 95.4%(6/128)of the difference values within the limits of agreement with 95% CI=(0.405, 2.408). The Passing–Bablok regression equation between the inactivated and noninactivated VPA concentrations was VPA_(inactivated)=1.016×VPA_(noninactivated)-0.017 2, which was with 95% CI=(-2.254, 2.183) for the intercept and(0.979, 1.050) for the slope. The Pearson correlation coefficient was 0.9861 with P<0.01, indicating that the VPA plasma concentration values had a good correlation before and after inactivation.CONCLUSION The plasma sample treated with inactivation at 56℃ for 30 min coupled with protein precipitation has little effect on the determination of plasma concentration of VPA by LC-MS, which can be used for the routine TDM of VPA.