Duncan M W, Compton P, Lazarus L, Smythe G A
Garvan Institute of Medical Research, St. Vincent's Hospital, Sydney, Australia.
N Engl J Med. 1988 Jul 21;319(3):136-42. doi: 10.1056/NEJM198807213190303.
We compared the value of plasma samples with that of 24-hour urine samples in identifying patients with pheochromocytoma among those with hypertension. We employed specific gas chromatographic-mass spectrometric analysis of both urine and plasma for simultaneous assay of norepinephrine and its neuronal metabolite 3,4-dihydroxyphenylglycol (DHPG). The study population consisted of 1086 patients with hypertension, among them 25 patients with proved pheochromocytoma. Reference ranges for free norepinephrine and DHPG in plasma and urine were established. Measurement of free norepinephrine in 24-hour urine samples provided the best index of a pheochromocytoma. This technique had 100 percent sensitivity and 98 percent specificity among 1192 urine samples, as compared with 82 percent sensitivity and 95 percent specificity among 358 plasma samples. Simultaneous measurement of norepinephrine and DHPG in urine further improved specificity (to 99 percent), but the use of the ratio of norepinephrine to DHPG reduced sensitivity (to 95 percent), since some patients with pheochromocytoma secrete large amounts of DHPG. We therefore recommend measurement of 24-hour urinary levels of free norepinephrine for the diagnosis of pheochromocytoma and suggest that simultaneous analysis for DHPG may sometimes prove useful in reducing the rate of false positive results.
我们比较了血浆样本和24小时尿液样本在高血压患者中识别嗜铬细胞瘤患者的价值。我们对尿液和血浆均采用特定的气相色谱-质谱分析法，以同时测定去甲肾上腺素及其神经代谢产物3,4-二羟基苯乙二醇（DHPG）。研究人群包括1086例高血压患者，其中25例确诊为嗜铬细胞瘤。确定了血浆和尿液中游离去甲肾上腺素和DHPG的参考范围。测定24小时尿液样本中的游离去甲肾上腺素是嗜铬细胞瘤的最佳指标。在1192份尿液样本中，该技术的灵敏度为100%，特异性为98%，而在358份血浆样本中，灵敏度为82%，特异性为95%。同时测定尿液中的去甲肾上腺素和DHPG可进一步提高特异性（至99%），但使用去甲肾上腺素与DHPG的比值会降低灵敏度（至95%），因为一些嗜铬细胞瘤患者会分泌大量DHPG。因此，我们建议测定24小时尿游离去甲肾上腺素水平以诊断嗜铬细胞瘤，并建议同时分析DHPG有时可能有助于降低假阳性结果的发生率。
