Unger N, Hinrichs J, Deutschbein T, Schmidt H, Walz M K, Mann K, Petersenn S
Department of Endocrinology and Division of Laboratory Research, Medical Center, University of Duisburg-Essen, Essen, Germany.
Exp Clin Endocrinol Diabetes. 2012 Sep;120(8):494-500. doi: 10.1055/s-0032-1309007. Epub 2012 Jun 13.
Adrenal pheochromocytomas are neoplasms characterized by catecholamine excess. Determination of metanephrines by high-pressure liquid chromatography has been well established for the diagnosis of pheochromocytomas, demonstrating high sensitivity and specificity. This study evaluates the diagnostic value of newly available enzyme immunoassays for metanephrines in plasma and urine. Chromogranin A was studied as a potential additional diagnostic tool. Spontaneous blood samples and 24-h urine samples were collected in 149 subjects, including 24 histologically proven pheochromocytomas, 17 aldosterone-secreting and 21 cortisol-secreting adrenal adenomas, 30 nonfunctioning adrenal masses, 15 patients with essential hypertension and 42 healthy normotensive volunteers. Plasma and urinary metanephrine and normetanephrine as well as chromogranin A were determined and putative thresholds were calculated by ROC analysis. Plasma free normetanephrine was found to be the best single parameter with the highest sensitivity (89.5%) and specificity (98.3%) using a threshold of 167 pg/ml. Analysis of the combination of plasma free metanephrines revealed a similar sensitivity with lower specificity of 90.0%. Considering both urinary parameters demonstrated a slightly higher sensitivity (92.9%) with lower specificity (77.6%). ROC analysis revealed a threshold of 215 µg/l for chromogranin A with rather low sensitivity (73.9%) and specificity (74.2%). A weak positive correlation was found between the tumor size of pheochromocytomas and plasma metanephrine (r = 0.53, p ≤ 0.05) as well as chromogranin A (r = 0.60, p ≤ 0.01). In conclusion, plasma free and urinary metanephrines measured by enzyme immunoassays are convenient and reliable parameters for the diagnosis of pheochromocytoma. In contrast, CgA demonstrated poor sensitivity and specificity.
肾上腺嗜铬细胞瘤是一类以儿茶酚胺过量为特征的肿瘤。通过高压液相色谱法测定甲氧基肾上腺素已被广泛用于嗜铬细胞瘤的诊断，具有高敏感性和特异性。本研究评估了新可用的血浆和尿液中甲氧基肾上腺素酶免疫测定法的诊断价值。嗜铬粒蛋白A作为一种潜在的辅助诊断工具进行了研究。收集了149名受试者的自发血样和24小时尿样，包括24例经组织学证实的嗜铬细胞瘤、17例分泌醛固酮的肾上腺腺瘤和21例分泌皮质醇的肾上腺腺瘤、30例无功能肾上腺肿块、15例原发性高血压患者和42例健康血压正常志愿者。测定血浆和尿液中的甲氧基肾上腺素、去甲氧基肾上腺素以及嗜铬粒蛋白A，并通过ROC分析计算推定阈值。发现血浆游离去甲氧基肾上腺素是最佳单一参数，阈值为167 pg/ml时，敏感性最高（89.5%），特异性最高（98.3%）。血浆游离甲氧基肾上腺素组合分析显示敏感性相似，但特异性较低，为90.0%。综合考虑两种尿液参数，敏感性略高（92.9%），但特异性较低（77.6%）。ROC分析显示嗜铬粒蛋白A的阈值为215 μg/l，敏感性相当低（73.9%），特异性也低（74.2%）。在嗜铬细胞瘤的肿瘤大小与血浆甲氧基肾上腺素（r = 0.53，p≤0.05）以及嗜铬粒蛋白A（r = 0.60，p≤0.01）之间发现了弱正相关。总之，通过酶免疫测定法测定的血浆游离和尿液甲氧基肾上腺素是诊断嗜铬细胞瘤方便且可靠的参数。相比之下，嗜铬粒蛋白A的敏感性和特异性较差。
