Department of Endocrinology and Metabolic Diseases, University of Groningen, University Medical Center Groningen, Groningen, the Netherlands.
Department of Laboratory Medicine, University of Groningen, University Medical Center Groningen, Groningen, the Netherlands.
Clin Chem. 2021 Aug 5;67(8):1090-1097. doi: 10.1093/clinchem/hvab064.
Measurements of plasma free metanephrines are recommended for diagnosing pheochromocytomas and paragangliomas (PPGL). Metanephrines can be detected in saliva with LC-MS/MS with sufficient analytical sensitivity and precision. Because collecting saliva is noninvasive and less cumbersome than plasma or urine sampling, we assessed the diagnostic accuracy of salivary metanephrines in diagnosing PPGL.
This 2-center study included 118 healthy participants (44 men; mean age: 33 years (range: 19--74 years)), 44 patients with PPGL, and 54 patients suspected of PPGL. Metanephrines were quantified in plasma and saliva using LC-MS/MS. Diagnostic accuracy; correlation between plasma and salivary metanephrines; and potential factors influencing salivary metanephrines, including age, sex, and posture during sampling, were assessed.
Salivary metanephrines were significantly higher in patients with PPGL compared with healthy participants (metanephrine (MN): 0.19 vs 0.09 nmol/L, P < 0.001; normetanephrine (NMN): 2.90 vs 0.49 nmol/L, P < 0.001). The diagnostic sensitivity and specificity of salivary metanephrines were 89% and 87%, respectively. Diagnostic accuracy of salivary metanephrines was 88%, with an area under the ROC curve of 0.880. We found a significant correlation between plasma and salivary metanephrines (Pearson correlation coefficient: MN, 0.86, P < 0.001; NMN, 0.83, P < 0.001). Salivary NMN concentrations were higher when collected in a seated position compared with supine (P < 0.001) and increased with age (P < 0.001).
Salivary metanephrines are a promising tool in the biochemical diagnosis of PPGL. Salivary metanephrines correlate with plasma free metanephrines and are increased in patients with PPGL. At this time, however, salivary metanephrines cannot replace measurement of plasma free metanephrines.
血浆游离甲氧基肾上腺素的测量被推荐用于诊断嗜铬细胞瘤和副神经节瘤(PPGL)。LC-MS/MS 可以检测唾液中的甲氧基肾上腺素,具有足够的分析灵敏度和精度。由于收集唾液比采集血浆或尿液更无创且不繁琐,因此我们评估了唾液中甲氧基肾上腺素在诊断 PPGL 中的诊断准确性。
这项 2 中心研究纳入了 118 名健康参与者(44 名男性;平均年龄:33 岁(范围:19-74 岁))、44 名 PPGL 患者和 54 名疑似 PPGL 患者。使用 LC-MS/MS 定量检测血浆和唾液中甲氧基肾上腺素。评估了诊断准确性;血浆和唾液中甲氧基肾上腺素之间的相关性;以及包括年龄、性别和采样时的体位在内的潜在影响唾液中甲氧基肾上腺素的因素。
与健康参与者相比,PPGL 患者的唾液中甲氧基肾上腺素显著升高(甲氧基肾上腺素(MN):0.19 与 0.09 nmol/L,P<0.001;去甲甲氧基肾上腺素(NMN):2.90 与 0.49 nmol/L,P<0.001)。唾液中甲氧基肾上腺素的诊断敏感性和特异性分别为 89%和 87%。唾液中甲氧基肾上腺素的诊断准确性为 88%,ROC 曲线下面积为 0.880。我们发现血浆和唾液中甲氧基肾上腺素之间存在显著相关性(Pearson 相关系数:MN,0.86,P<0.001;NMN,0.83,P<0.001)。与仰卧位相比,坐位时唾液 NMN 浓度更高(P<0.001),并随年龄增加而增加(P<0.001)。
唾液中甲氧基肾上腺素是 PPGL 生化诊断的有前途的工具。唾液中甲氧基肾上腺素与血浆游离甲氧基肾上腺素相关,并且在 PPGL 患者中升高。然而,目前唾液中甲氧基肾上腺素不能替代血浆游离甲氧基肾上腺素的测量。