目的 建立一种液相色谱串联质谱（Liquid Chromatography Tandem Mass Spectrometry, LC-MS/MS）法检测人体血清中甲状旁腺激素（Parathyroid hormone，PTH）并对基于LC-MS/MS法和免疫法的 PTH检测系统进行方法学比较。

方法 血清以抗PTH抗体包被的聚苯乙烯珠免疫富集，后弃去血清并清洗聚苯乙烯珠，加胰蛋白酶酶解后上机检测。在正离子模式下，以多反应监测（Multiple Reaction Monitoring，MRM）技术，使用电喷雾电离（Electrospray Ionization, ESI）方法检测血清 PTH。评价PTH1-44片段对PTH的干扰。对不同PTH浓度水平的血清连续5天进行重复检测，评估方法的精密度。同时对方法的检测限（Limit of Detection, LOD）、定量限（Limit of Quantitation, LOQ）、基质效应、回收率、线性范围及血清样本的稳定性进行评价。检测50例患者血清中PTH的含量，评估LC-MS/MS法与电化学发光免疫测定法（Electrochemiluminescence Immunoassay, ECLIA）的一致性。

结果 本研究建立的LC-MS/MS法可检测血清PTH的浓度。该方法化合物的保留时间约为4.0 min，特异性高，无明显干扰。在30~4000 pg/ml范围内线性良好，相关系数r大于0.99。 LC-MS/MS法测定血清PTH的重现性为5.23%~6.59%，实验室内不精密度为7.55%~13.53%。LOD和LOQ分别为25 pg/ml和30 pg/ml。血清PTH加标回收率为92.86%~97.23%。ECLIA法与LC-MS/MS法比对的回归方程为y = 1.06 x – 24.57，平均百分偏倚为-14.72%。

结论 本研究成功建立了LC-MS/MS检测血清PTH的方法，该方法特异性高、无明显干扰，与ECLIA方法的相关性较好，可用于临床评价人血清PTH的含量。

Objective A liquid chromatography-tandem mass spectrometry (LC-MS/MS) method was established for the detection of parathyroid hormone (PTH) in human serum, and the methodological comparison of different methodological detection systems for PTH were conducted.

Methods The serum was immunologically enriched with polystyrene beads coated with anti-PTH antibody and then the serum was discarded. The enriched PTH was hydrolyzed by trypsin and tested by LC-MS/MS. In the positive ion mode, PTH was detected by electrospray ionization (ESI) and multiple reaction monitoring (MRM). We have evaluated the interference of PTH1-44. Serum with different PTH concentration levels were detected for 5 consecutive days to investigate the precision of the method. The limits of detection (LOD) and quantitation (LOQ), matrix effects, recovery rate, linear range and stability of serum were evaluated. The concentration of PTH in serum of 50 patients was determined to evaluate the consistency of LC-MS/MS and electrochemiluminescence immunoassay (ECLIA).

Results Serum PTH can be detected by the LC-MS/MS method established in this study. The retention time of the compounds was about 4.0 min. The method was with high specificity and no significant interference. In the range of 30-4000pg/ml, the linearity showed well, and the correlation coefficient was greater than 0.99. The reproducibility ranged from 5.23% to 6.59% and laboratory imprecision ranged from 7.55% to 13.53%. The LOD and LOQ were 25 pg/ml and 30 pg/ml, respectively. The recoveries of PTH were 94.19%~98.36%. The regression equation of comparison between ECLIA and LC-MS/MS was y = 1.06 x – 24.57, and average percentage bias was -14.72%.

Conclusion This study successfully established a method for detection of serum PTH by LC-MS/MS, which was specific, no significant interference and can be used for clinical evaluation of human serum PTH concentration. The correlation between ECLIA and LC-MS/MS was fine.