Robinson Research Institute and Adelaide School of Medicine, University of Adelaide, Adelaide, South Australia, Australia.
J Pineal Res. 2019 Aug;67(1):e12572. doi: 10.1111/jpi.12572. Epub 2019 Apr 12.
There has been increased interest in the measurement of melatonin in plasma and saliva recently either as a marker of circadian phase or to understand the physiological role of melatonin. For both situations, there is a need for a specific assay for melatonin that is sensitive enough to detect low concentrations (<2 pg/mL). Since the mid-1970s, there have been many assays developed to measure melatonin in blood and saliva. Radioimmunoassays and ELISA have predominated because of their relative simplicity and high throughput. In this review, I show that the early radioimmunoassays while providing valuable information about nocturnal melatonin levels in humans, generally produced inaccurate basal (daytime) levels. Mass spectrometry assays, however, have provided us with the target values that immunoassays need to achieve, that is, daytime plasma melatonin levels <1 pg/mL. There are now many contemporary commercial assays available utilising both RIA and ELISA technologies, but not all achieve the standards set by the mass spectrometry assays. The performance of these assays is reviewed. I conclude with recommendations on issues researchers need to consider when conducting melatonin studies, including the importance of time of day of collection, validation of assays, the potential causes of poor assay specificity at low levels, the advantages/disadvantages of using saliva vs plasma and extraction assays vs direct assays, kit manufacturers responsibilities and the reporting requirements when publishing melatonin studies.
最近，人们对血浆和唾液中褪黑素的测量越来越感兴趣，无论是作为生物钟相位的标志物，还是为了了解褪黑素的生理作用。对于这两种情况，都需要有一种足够灵敏的、能够检测低浓度（<2 pg/mL）褪黑素的特定检测方法。自 20 世纪 70 年代中期以来，已经开发出许多用于测量血液和唾液中褪黑素的方法。放射免疫分析和 ELISA 因其相对简单和高通量而占主导地位。在这篇综述中，我表明，早期的放射免疫分析虽然提供了有关人类夜间褪黑素水平的有价值的信息，但通常产生不准确的基础（白天）水平。然而，质谱分析为免疫分析提供了需要达到的目标值，即白天血浆褪黑素水平<1 pg/mL。现在有许多利用 RIA 和 ELISA 技术的当代商业检测方法，但并非所有方法都能达到质谱检测方法设定的标准。本文对这些检测方法的性能进行了回顾。最后，我提出了一些建议，供研究人员在进行褪黑素研究时考虑，包括采集时间、检测方法的验证、在低水平时检测方法特异性差的潜在原因、使用唾液与血浆、提取与直接检测的优缺点、试剂盒制造商的责任以及发表褪黑素研究报告的要求。
