OBJECTIVES: Inconsistent elevation of catecholamines (CAs) and metanephrines (MNs) was observed in pheochromocytomas/paragangliomas (PPGLs). This study aimed to explore its potential causes and report the diagnostic efficacy of MNs and CAs in a large Chinese PPGL cohort. METHODS: Clinical data and results of hormone tests were retrospectively collected. The sensitivity of plasma MNs and 24h-urinary CAs was analyzed. Clinical characteristics were compared between patients with positive and negative biochemical results, and among those with inconsistent elevation of MNs and CAs. RESULTS: Seven hundred and three patients were included, with a median onset age of 41.0 years. Plasma MNs (93% ~ 99%) showed prior diagnostic sensitivity to 24h-urinary CAs (74% ~ 89%). Patients with negative biochemical results presented as a smaller tumor (1.7 cm vs. 4.3 cm, P = 0.001), a higher proportion of normal blood pressure (60.0% vs. 20.5%, P = 0.002) and negative CONCLUSIONS: Plasma MNs exhibited a superior sensitivity than 24-h-urinary CAs in the Chinese PPGL diagnosis. Patients with a small tumor, normal blood pressure and negative