The Consistency of Plasma Catecholamines and Metanephrines Analysis in China: A Comparison of Three Mainstream Commercially Available Liquid Chromatography Tandem Mass Spectrometry Kit Methods.

Objective: The consistency of plasma catecholamines and metanephrines measurements is crucial for the screening and diagnosis in pheochromocytomas and paragangliomas (PPGLs). There are many commercially available kits for plasma catecholamines and metanephrines testing, but their performance and consistency information are unknown. This study evaluated the performance of three mainstream commercially available LC-MS/MS kit methods and evaluated their consistency.

Methods: Performance validation of three kit methods was performed according to Clinical Laboratory Standards Institute (CLSI) document C-62A. 40 plasma samples from patients tested for PPGLs were analyzed in three mainstream commercially available kit methods. Agreement of test results from different kit methods was assessed by Passing-Bablok regression and Bland-Altman analysis. Recalibration using uniform calibrations was performed to identify the possible calibration difference.

Results: The performance of three mainstream commercially available LC-MS/MS kit methods was satisfied. The mean deviations ranges were as follows: epinephrine(E), -41.1% ~ -2.4%; norepinephrine (NE), -34.3% ~ -19.1%; metanephrine (MN), -6.5% ~ 0.3% and normetanephrine (NMN), -2.3% to 0.0%. After recalibration, the mean deviation ranges of the E and NE were reduced remarkably (E: -18% to -2.4%, NE: -19.1% to 8.0%).

Conclusions: For MN and NMN, the consistency between the three commercially available kit methods is acceptable. The results for the E and NE showed unsatisfying comparability for almost all method pairs. The application of uniform calibrators could improve consistency among the mainstream systems for the measurement of plasma catecholamines.