It has been more than 80 years since the discovery of vitamin D and its ability to cure rickets in children. Vitamin D is a secosteroid and comes in two distinct forms, vitamin D2 and vitamin D3. During the last 40 years, the synthesis and metabolism of vitamin D were elucidated and more than 50 metabolites of vitamin D have been discovered, though commercial measurement procedures have been developed for only a few of them. The clinical significance of vitamin D in calcium and phosphorus homeostasis is well appreciated. However, recent epidemiological data have indicated that it has several extra-skeletal physiologic actions which are still a matter of scientific debate. Both research findings and the debate around the interpretation of the research results have created increased interest in more measurements of vitamin D. With the ever growing family of measurable vitamin D metabolites and the measuring techniques comes a question: What metabolic product will provide the right answers and which is the best way to measure it. The right choice of analytical technique is connected with the question of which metabolite we aim to measure, what is its serum concentration, and the purpose of the measurement. The aim of the first part of this review is to provide a brief overview of vitamin D metabolism and a more detailed analysis of the existing methods and the status of standardization for the measurement of 25-hydroxyvitamin D.

中文翻译：

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维生素D代谢物的测定：维生素D的I部分代谢和25-羟基维生素D的测定。

自发现维生素D及其治愈儿童病的能力以来，已有80多年的历史了。维生素D是一种类固醇，有两种不同的形式，即维生素D2和维生素D3。在过去的40年中，阐明了维生素D的合成和代谢，并发现了50多种维生素D代谢物，尽管仅为其中几种开发了商业测量程序。维生素D在钙和磷稳态中的临床意义已广为人知。但是，最近的流行病学数据表明，它具有几种骨骼外的生理作用，这仍然是科学争论的问题。研究结果和围绕研究结果解释的争论都引起了人们对更多测量维生素D的兴趣。随着可测量的维生素D代谢产物家族的不断增长，出现了一个问题：哪种新陈代谢的产品将提供正确的答案，哪种是最佳的测量方法。分析技术的正确选择与我们要测量的代谢物，其血清浓度是多少以及测量目的有关。这篇综述的第一部分的目的是简要概述维生素D的代谢，并对现有方法和25-羟基维生素D测量的标准化状况进行更详细的分析。分析技术的正确选择与我们要测量的代谢物，其血清浓度是多少以及测量目的有关。这篇综述的第一部分的目的是简要概述维生素D的代谢，并对现有方法和25-羟基维生素D测量的标准化状况进行更详细的分析。分析技术的正确选择与我们要测量的代谢物，其血清浓度是多少以及测量目的有关。这篇综述的第一部分的目的是简要概述维生素D的代谢，并对现有方法和25-羟基维生素D测量的标准化状况进行更详细的分析。