摘要
目的 检测24小时尿游离甲氧基肾上腺素（MN）和甲氧基去甲肾上腺素（NMN）是诊断嗜铬细胞瘤的首选筛查方法之一,需寻求24小时尿液收集和游离NMN、MN获得这两个前处理过程中尿液酸化处理的安全可控方式。方法 随机尿标本用于本研究,观察在添加或不添加浓盐酸及在室温或较高温（34℃）存放24小时和在不同酸性条件下（p H值为2、3、4）进行酸水解对尿游离NMN/MN水平的影响。结果 首先发现尿液在室温或较高温条件下不添加盐酸进行酸化存放24小时游离NMN/MN并没有显著降解。之后统计发现不同患者24小时尿量存在较大变化,常规方法留尿过程加入固定剂量的酸会引起p H值的波动（p H值2~4）。通过调节尿液p H值,发现在不同酸性条件进行酸水解尿游离NMN的检测,其水平存在显著差异,p H值大于等于4不能达到酸水解的目的。最后利用40份随机尿标本验证发现尿液不加酸存放24小时但水解时酸化至p H 2为更可控的尿液酸化方式。结论 24小时尿留取过程不必添加盐酸但水解前用盐酸调节p H值到2是尿游离NMN、MN检测更加安全可控的前处理方式。
Objective Measurements of 24-h fractionated urinary fractionated metanephrine and normetanephrine are used for the diagnosis of pheochromocytoma, but adequate information is needed regarding collection and storage. Methods Spot urine samples were collected from 70 volunteers. Aliquots were preserved for 24 hours at room temperature or 34℃ with or without acidification with 12N hydrochloric acid. Samples were tested the efficacy of hydrolysis at different acid conditions （ pH 2, 3 and 4）. Results No clinically relevant degradation was observed for the fractionated metanephrines in unpreserved urine samples after 24 h at room temperature and 34℃. Acidification to pH 4 was not effective for hydrolysis. Compared with acidification during colllection, acidified to pH 2 before acid hydrolysis was a better way for detection of fractionated metanephrine and normetanephrine. Conclusion Preservation of urine samples with hydrochloric acid for measurements of urinary fractionated metanephrine and normetanephrine is not necessary. Acidification to pH 2 before hydrolysis is a more effective and practical method.
出处
《标记免疫分析与临床》
CAS
2016年第6期696-699,共4页
Labeled Immunoassays and Clinical Medicine
