Vitamin D deficiency (VDD) is a global public health problem. Inaccurate methods for measuring plasma 25-hydroxyvitamin D (25[OH]D) may have contributed to the reported high prevalence of VDD. We hypothesized that the most commonly used assay for vitamin D status, chemiluminescence immunoassay (CLIA), underestimates 25(OH)D levels and thus overestimates VDD. Using both liquid chromatography-tandem mass spectrometry and CLIA for plasma 25(OH)D, we evaluated the prevalence of VDD in adolescents (11-16 years-old; n = 410) by both methods in a cross-sectional study. Subjects were selected from public middle schools from all the 6 Governorates of Kuwait using stratified multistage cluster random sampling. Cohen κ agreement, linear regression, and Bland-Altman plots were used to evaluate the classification of VDD by the 2 methods. VDD (25[OH]D < 50 nmol/L) was 85.9% with CLIA and 81.2% with liquid chromatography-tandem mass spectrometry. There was a good agreement between the 2 methods in classifying the study subjects as deficient, insufficient, or sufficient (κ = 85.1%, P < .001). The between-assay bias was very small with a mean percentage difference < 1% from the mean value of the 25(OH)D as assessed by the 2 methods. These data did not support our hypothesis, and we conclude that the routine methods used for plasma 25(OH)D levels have no or little impact on evaluating VDD as a public health problem or in clinical management.

中文翻译：

---

用于血浆 25-羟基维生素 D 分析的常规化学发光检测并没有高估青少年维生素 D 缺乏症的患病率

维生素 D 缺乏症 (VDD) 是一个全球性的公共卫生问题。测量血浆 25-羟基维生素 D (25[OH]D) 的不准确方法可能是导致 VDD 高发的原因。我们假设最常用的维生素 D 状态测定法，化学发光免疫测定法 (CLIA)，低估了 25(OH)D 水平，从而高估了 VDD。使用液相色谱-串联质谱法和 CLIA 检测血浆 25(OH)D，我们在横断面研究中通过两种方法评估了青少年（11-16 岁；n = 410）中 VDD 的患病率。受试者使用分层多阶段整群随机抽样从科威特所有 6 个省的公立中学中选出。Cohen κ 一致性、线性回归和 Bland-Altman 图用于评估 2 种方法对 VDD 的分类。VDD (25[OH]D < 50 nmol/L) CLIA 为 85.9%，液相色谱-串联质谱法为 81.2%。两种方法在将研究对象分类为缺陷、不足或充足方面具有良好的一致性（κ = 85.1%，P < .001）。测定间偏差非常小，与两种方法评估的 25(OH)D 平均值的平均百分比差异 < 1%。这些数据不支持我们的假设，我们得出结论，用于血浆 25(OH)D 水平的常规方法对将 VDD 评估为公共卫生问题或临床管理没有影响或影响很小。测定间偏差非常小，与两种方法评估的 25(OH)D 平均值的平均百分比差异 < 1%。这些数据不支持我们的假设，我们得出结论，用于血浆 25(OH)D 水平的常规方法对将 VDD 评估为公共卫生问题或临床管理没有影响或影响很小。测定间偏差非常小，与两种方法评估的 25(OH)D 平均值的平均百分比差异 < 1%。这些数据不支持我们的假设，我们得出结论，用于血浆 25(OH)D 水平的常规方法对将 VDD 评估为公共卫生问题或临床管理没有影响或影响很小。