比较两种自动化免疫分析仪对血清25-羟维生素D的测定

目的 比较Architect I2000和DiaSorin LIAISON两种自动化免疫分析仪对血清25-羟维生素D［25(OH)D］测定的相关性及差异，为临床诊疗提供参考依据。方法 根据美国临床实验室标准化委员会（NCCLS）的EP9-A2文件，分别在两个系统检测三个水平（L1, L2, L3）的25(OH)D质控品，通过Excel 2007软件分析两个系统测定25(OH)D的不精密度。收集266份临床样本进行25(OH)D检测，将样本分成两份在本实验室Architect I2000和DiaSorin LIAISON系统同时进行检测。采用MedCalc软件进行统计学分析，以Passing-Bablok回归和Pearson相关系数分析两种方法测定结果之间的相关性，以Bland-Altman比较它们之间的差异。结果 在不精密度评估中，两个系统（DiaSorin LIAISON vs Architect I2000）三个质控水平（L1, L2, L3）的总不精密度分别为L1: 8.86% vs 7.89%，L2: 5.82% vs 4.67%，L3: 6.66% vs 5.71%。Passing-Bablok和Pearson分析显示Architect I2000和DiaSorin LIAISON间相关系数为r=0.98。Bland-Altman分析结果显示，Architect I2000检测的25(OH)D比DiaSorin LIAISON的平均高7.2ng/ml，随着25(OH)D的增高，两者的差值越来越大，最大差值可达43.3ng/ml。结论 Architect I2000和DiaSorin LIAISON两个系统检测的25(OH)D相关性较好。Architect I2000精密度优于DiaSorin LIAISON，Architect I2000系统得到25(OH)D的结果更为准确，与临床诊断更相符。     

健康学龄前351名儿童25-羟维生素D水平及影响因素

目的 了解上海市学龄前儿童的维生素D水平并分析其影响因素,为防治该地区维生素D缺乏提供理论依据。方法 随机抽取上海市浦东新区3家幼儿园共351名3～6岁学龄前儿童(男:185名,女:166名),采用液相色谱串联质谱法(LC-MS/MS)测定测血清25-羟维生素 D[25-(OH)D]水平,并通过标准问卷获得相关影响因素数据。结果 受试学龄前儿童血清25-羟维生素 D[25-(OH)D]的平均水平为(28.14±6.70) ng/ml。维生素D缺乏[25-(OH)D＜20 ng/ml]为35例(10.0％),维生素D适宜水平(20～100 ng/ml)为316例(90.0%)。多因素分析结果显示维生素D制剂补充频率低及大年龄组(≥6岁)是学龄前儿童25-(OH)D缺乏的高危因素(P＜0.05)。结论 年龄和维生素D制剂补充与学龄前儿童维生素D水平明显相关,大年龄组(≥6岁)儿童维生素D制剂补充率相对较低。针对目前学龄前儿童仍存在维生素D缺乏的情况,应该加强儿童保健的科普教育,结合个体情况提高维生素D的补充率,同时增加儿童户外活动,促进学龄前儿童健康。     

健康学龄前351名儿童25-羟维生素D水平及影响因素

目的 了解上海市学龄前儿童的维生素D水平并分析其影响因素,为防治该地区维生素D缺乏提供理论依据。方法 随机抽取上海市浦东新区3家幼儿园共351名3～6岁学龄前儿童(男:185名,女:166名),采用液相色谱串联质谱法(LC-MS/MS)测定测血清25-羟维生素 D[25-(OH)D]水平,并通过标准问卷获得相关影响因素数据。结果 受试学龄前儿童血清25-羟维生素 D[25-(OH)D]的平均水平为(28.14±6.70) ng/ml。维生素D缺乏[25-(OH)D＜20 ng/ml]为35例(10.0％),维生素D适宜水平(20～100 ng/ml)为316例(90.0%)。多因素分析结果显示维生素D制剂补充频率低及大年龄组(≥6岁)是学龄前儿童25-(OH)D缺乏的高危因素(P＜0.05)。结论 年龄和维生素D制剂补充与学龄前儿童维生素D水平明显相关,大年龄组(≥6岁)儿童维生素D制剂补充率相对较低。针对目前学龄前儿童仍存在维生素D缺乏的情况,应该加强儿童保健的科普教育,结合个体情况提高维生素D的补充率,同时增加儿童户外活动,促进学龄前儿童健康。     

芜湖市6373例儿童血清25-羟维生素D3水平监测结果分析

目的 了解芜湖市儿童25-羟维生素D3(25-(OH) D3)的营养状况.方法 选取在芜湖市妇幼保健院进行25-(OH) D3检测的儿童共6373人,分析不同性别、年龄、季节及湿疹儿童的25-(OH) D3水平.结果 芜湖市6373名儿童血清25-(OH) D3平均浓度为(34.53 ±8.25) ng/ml,维生素D营养不良检出率为21.60％.以秋季儿童血清水平最高(39.39±7.44) ng/ml,不同季节儿童血清25-(OH) D3浓度(F=178.720,P＜0.001)及维生素D营养不良检出率(x2=294.139,P＜0.001)差异有统计学意义.患湿疹儿童血清25-(OH) D3浓度更低(F血清25-(OH)D3=7.441,P＜0.001),维生素D营养不良检出率更高(x2=5.519,P=0.019),差异有统计学意义.结论 芜湖市儿童血清25-(OH) D3水平、维生素D营养不良检出率与季节相关,湿疹患儿血清25-(OH) D3浓度低,维生素D营养不良检出率高.     

超高效液相色谱-串联质谱法测定血清中25-羟基维生素D和维生素K_1

目的建立超高效液相色谱-串联质谱(ultra-performance liquid chromatography-tandem mass spectrometry,UPLC-MS/MS)同时测定血清中25-羟基维生素D_2[25-hydroxyvitamin D_2, 25(OH)D_2]、25-羟基维生素D_3[25-hydroxyvitamin D_3,25(OH)D_3]和维生素K_1(vitamin K_1,VK_1)的方法,并用此方法诊断维生素缺乏症,评估人群营养状况。方法血清标本采用乙腈沉淀血清蛋白,正己烷提取。采用BEH C_(18)色谱柱(100 mm×2.1 mm,1.7μm)进行分离,以甲醇-0.1%甲酸水溶液梯度洗脱。质谱采用电喷雾正离子模式和多反应监测检测。以稳定同位素标记的d_6-25(OH)D_3、d_7-维生素K_1作为内标定量。结果 25(OH)D_2、25(OH)D_3和维生素K_1分别在浓度为5.0～75.0 ng/mL、2.0～81.5 ng/mL和0.3～12.0 ng/mL的范围内呈良好线性关系,相关系数r0.995;检出限分别为1、0.25和0.1 ng/mL,定量限分别为3、0.75和0.3 ng/mL;血清基质中3种维生素高中低3个浓度水平的精密度均5.0%、加标回收率为98.5%～104.3%(n=6)。结论本研究建立的UPLC-MS/MS方法检测血清中25(OH)D_2、25(OH)D_3和维生素K_1灵敏度高、准确性好,适用于人群维生素D及维生素K_1营养状况的监测。     

健康儿童脂溶性维生素A、D、E现状分析

目的　了解北京地区健康儿童血清维生素A、D、E水平。方法　采集北京居住半年以上健康体检儿童的临床资料,利用反相高效液相色谱荧光检测法测定血清维生素A、维生素E,液相色谱串联质谱法测定血清25-羟维生素D ［25-(OH)D］水平。结果　健康体检儿童共1 538例,维生素A平均（0.30±0.07）mg/L,亚临床缺乏占5.2%（80/1 538）,其中＜3岁占70.0%（56/80）;可疑亚临床缺乏占47.1%（724/1 538）,其中＜3岁占50.1%（363/724）。2岁及以下婴幼儿血清水平为（0.28±0.07）mg/L,处于可疑亚临床缺乏状态,母乳喂养儿维生素A水平最低（0.25±0.06）mg/L。268例儿童检测血清25-(OH)D,平均水平为（25.52±10.88）ng/L,缺乏占30.2%（81/268）,其中≥3岁占92.6%（75/81）。血清维生素E平均（9.21±2.31）mg/L,正常占85.6%（1 311/1 532）,缺乏仅为0.6%（9/1 532）,不足占13.8%（212/1 532）,且以＞3岁为主。维生素A、25-(OH)D、维生素E与年龄的Spearman相关系数分别为0.197、－0.420、－0.319。结论　健康体检儿童维生素A以可疑亚临床缺乏为主,婴幼儿维生素D营养状况良好,学龄及青少年维生素D缺乏或不足问题明显,维生素E缺乏少见。     

液相色谱-串联质谱法检测人血清25羟维生素D_3水平及条件控制分析

目的人血清25羟维生素D3[25-(OH)D3]测定对于评价体内维生素D的水平十分重要。本文拟建立液相色谱-串联质谱法(LC-MS/MS)测定人血清25-(OH)D3的方法。方法人血清样本(400μl)用纯甲醇去蛋白,离心后用正己烷进行液-液萃取。采用大气压化学离子源(APCI源),正离子多反应监测模式。色谱柱:Waters ACQUITY UPLC BEH C18色谱柱(50mm×2.1mm,1.7μm);流动相:100%甲醇;流速:0.2ml/min。结果 LC-MS/MS的检出限为1.0ng/ml,25-OHD3浓度在6～120ng/ml范围内,峰面积与浓度线性关系良好(r=0.999),平均回收率为99.5%(范围:97.1%～103.4%),RSD为4.7%。分别用LC-MS/MS和放射免疫法检测53例血清样本,两种方法的平均浓度分别为23.69ng/ml和20.1ng/ml,LC-MS/MS比放射免疫法(RIA)平均高17.69%(P=0.083)。二者的相关性良好,RIA=LC-MS/MS-3.57,相关系数为0.883。结论本方法具有良好的灵敏度、准确度、精确度,易于操作,与放射免疫法相关性好,可用于测定人血清中25-(OH)D3的含量。     

宝鸡地区1 874例0～7岁儿童维生素D水平调查研究

目的 调查宝鸡地区0～7岁儿童血清25(OH)D水平,为0～7岁儿童合理摄入及补充维生素D提供科学依据。方法 选用2011年1月-2014年6月来宝鸡市第二人民医院儿童保健科体检儿童1 874例。其中男1 005例,女869例,采用国际先进的高效液相色谱-串联质谱法测定所有研究对象的血清25(OH)D水平。结果 1)宝鸡市0～7岁儿童血清25(OH)D均值为(21.02±13.27)ng/ml,996例(53.15%)存在血清25(OH)D缺乏,390例(20.81%)存在血清25(OH)D不足,0月～组最低,3岁～组最高。 2)市区(金台、渭滨)、陈仓区、周边县区、外地血清25(OH)D水平依次递增。 3)夏季和秋季的血清25(OH)D水平显著高于春季和冬季,且夏、秋季儿童血清25(OH)D缺乏、不足率显著低于春、冬季。4)超重与非超重儿童血清25(OH)D分别为(24.67±10.61)ng/ml和(20.11±11.57)ng/ml,而肥胖与非肥胖儿童血清25(OH)D分别为(25.37±10.25)ng/ml和(20.56±10.74)ng/ml,组间血清25(OH)D差异均有统计学意义。5)不同性别血清25(OH)D差异无统计学意义。结论 宝鸡市0～7岁儿童血清25(OH)D普遍缺乏,应采取积极、有效的措施加强0～7岁儿童维生素D的摄入和补充。     

超高效液相色谱-串联质谱法同时快速检测微量血清中6种脂溶性维生素

目的 建立超高效液相色谱-串联质谱法（UPLC-MS/MS）同时快速检测微量血清中维生素A、维生素D（25-OH-VD2 、25-OH-VD3 ）、维生素E（α-、β-和γ-生育酚）的方法。方法 血清中脂溶性维生素经甲醇-乙腈（50:50, v/v)沉淀蛋白、正己烷萃取,以Phenomenex Kinetex F5色谱柱为分离柱,2.5 mmol/L甲酸铵-0.1%甲酸水溶液和甲醇为流动相,梯度洗脱,电喷雾电离（ESI+ ）、多反应监测（MRM）模式下检测,同位素内标法定量。结果 血清中6种脂溶性维生素线性范围内线性关系良好,相关系数 r >0.995;6种脂溶性维生素的检测限为0.20~1.25 ng/ml,定量限为0.39~3.88 ng/ml;加标回收率为86.6%~107.7%,日内精密度<9.6%,日间精密度<9.3%。NIST标准参照品SRM 968f验证方法准确度,结果偏差均在5%以内。结论 本方法准确度高、重现性好、用血量少,适于婴幼儿等采血困难者微量血样中多种脂溶性维生素的同时快速检测。     

阿尔茨海默病与维生素D水平的关系

目的,了解阿尔茨海默病（AD）患者体内维生素D营养状况,分析其血清25羟维生素D[25(OH)D ]水平与认知功能的关系,为临床补充维生素D制剂的干预研究提供依据。方法 回顾性分析本院113例住院AD患者血清总25(OH)D浓度与认知功能的关系。采用液相色谱-串联质谱法（LC-MS／MS）,定量测定AD患者血清25(OH)D2、25(OH)D3 和总25(OH)D浓度。按2011年美国医学科学院(IOM)的维生素D营养状况分级标准分组：维生素D充足组［25(OH)D≥75 nmol/L］、维生素D不足组［25(OH)D 50～75 nmol/L］、维生素D缺乏组［25(OH)D 25～50 nmol/L］和维生素D严重缺乏组［25(OH)D≤25 nmol/L］。结果 （1）113例AD患者血清总25(OH)D为（27.08±15.33）nmol/L,其中血清25(OH)D2为（1.23±0.93）nmol/L和25(OH)D3为（24.50±13.04）nmol/L;（2）60.18 %（68/113）患者维生素D严重缺乏、30.97 %（35/113）患者维生素D缺乏、7.97%（9/113）患者维生素D不足和0.88%（1/113）患者维生素D充足;（3）AD患者血清总25(OH)D浓度与MMSE总分的Spearman秩和相关分析呈正相关关系（r=0.202,P=0.032）。结论 住院AD患者严重缺乏维生素D,需要补充维生素D;血清总25(OH)D浓度与认知功能有正相关关系;补充维生素D制剂是否能提高认知功能,需要进一步进行随机双盲、安慰剂对照临床研究证实。     

25-Hydroxyvitamin D and 1,25-dihydroxyvitamin D of D2 and D3 origin in maternal and umbilical cord serum after vitamin D2 supplementation in human pregnancy

Serum concentrations of 25-hydroxyvitamin D (25-OHD) and 1,25-dihydroxyvitamin D [1,25-(OH)2D] of vitamin D2 and D3 origin were determined separately in 10 women before vitamin intake in early pregnancy, and repeated in maternal and cord serum obtained at delivery after 20 to 30 wk of vitamin D2 supplementation in a dose of 400 IU/day. Before supplementation 25-OHD2 and 1,25-(OH)D2D2 were present in just traceable or nondetectable concentrations, but the levels increased in all to a mean +/- 1 SD of 7.3 +/- 3.7 ng/ml and 37.2 +/- 18.1 pg/ml, respectively (p less than 0.0025), by the time of delivery. At delivery the total 25-OHD and 1,25-(OH)2D levels were always lower in the cord than in the maternal serum (30.7 +/- 14.2 versus 20.1 +/- 9.1 ng/ml, and 90.1 +/- 31.2 versus 37.3 +/- 11.6 pg/ml, p less than 0.0025). The paired concentrations of 25-OHD were closely related (r = 0.89, p less than 0.0005), while the association for 1,25-(OH)2D was not statistically significant (r = 0.53, p less than .01). The 25-OHD of D2 and D3 origin accounted for a similar proportion of the total 25-OHD in the maternal and cord serum (ratio of 25-OHD2 to 25-OHD3: 0.40 +/- 0.28 versus 0.45 +/- 0.29, p = NS), as did the respective 1,25-(OH)2D metabolites [ratio of 1,25-(OH)2D2 to 1,25-(OH)2D3: 0.73 +/- 0.35 versus 0.90 +/- 0.50, p = NS].(ABSTRACT TRUNCATED AT 250 WORDS)     

Effects of sun exposure and dietary vitamin D intake on serum 25-hydroxyvitamin D status in hemodialysis patients

BACKGROUND/OBJECTIVES

Vitamin D deficiency is common in hemodialysis patients. The aim of this study was to identify whether or not sun exposure and dietary vitamin D intake have effects on serum 25-hydroxyvitamin D (25(OH)D) status in hemodialysis (HD) patients. The objective was to identify the main determinants of serum vitamin D status in the study subjects.

SUBJECTS/METHODS

A cross-sectional study of 47 HD patients (19 males and 28 females) was performed. We assessed serum 25(OH)D and 1,25(OH)₂D levels between August and September 2012 and analyzed the prevalence of vitamin D deficiency in HD patients. To evaluate the determinants of serum 25(OH)D levels, we surveyed dietary vitamin D intake, degree of sun exposure, and outdoor activities. To compare biological variables, serum 25(OH)D was stratified as below 15 ng/ml or above 15 ng/ml.

RESULTS

Mean 25(OH)D and 1,25(OH)₂D levels were 13.5 ± 5.8 ng/ml and 20.6 ± 11.8 pg/ml, respectively. The proportions of serum 25(OH)D deficiency (< 15 ng/ml), insufficiency (15-< 30 ng/ml), and sufficiency (≥ 30 ng/ml) in subjects were 72.4%, 23.4%, and 4.3%, respectively. Prevalence of vitamin D deficiency in female patients was 78.6%, whereas that in males was 63.2% (P = 0.046). Vitamin D intake and sun exposure time were not significantly different between the two stratified serum 25(OH)D levels. Dietary intake of vitamin D did not contribute to increased serum 25(OH)D levels in HD patients. The main effective factors affecting serum 25(OH)D status were found to be the sun exposure and active outdoor exercise.

CONCLUSIONS

Hypovitaminosis D is common in HD patients and is higher in females than in males. Sun exposure is the most important determinant of serum 25(OH)D status in HD patients.     

Serum levels of vitamin D metabolites in children receiving total parenteral nutrition

Serum levels of 25-hydroxyvitamin D (25-OHD) and 1,25-dihydroxyvitamin D (1,25-(OH)2D) were measured on 19 occasions in seven children receiving total parenteral nutrition (TPN). The daily intakes of vitamin D3 ranged from 44 to 540 IU/day, and all serum samples were obtained after the same daily intake of vitamin D3 for more than 1 month. There was a significant positive correlation between serum 25-OHD levels and parenteral vitamin D3 intakes (r = 0.90, p less than 0.01). In this study, serum 25-OHD levels in all cases taking 200 to 360 IU/day of vitamin D3 were within the normal range. On the other hand, no significant correlation was found between serum 1,25-(OH)2D levels and vitamin D3 intakes, and serum 1,25-(OH)2D levels were normal or elevated in all cases.     

纯母乳喂养小婴儿及其母亲维生素D水平相关性研究

目的 分析出生28~42 d出现佝偻病临床表现的纯母乳喂养儿的血清维生素D水平及与其母亲血维生素D水平的相关性,为预防婴儿早期营养性佝偻病的发生提供理论依据。方法 对2016年4月-2017年10月来西北妇女儿童医院儿童保健科正常体检的年龄为28~42 d、并且表现有佝偻病早期症状和(或)体征的119例纯母乳喂养儿及其母亲静脉血25-羟维生素D[25-(OH)D]进行相关性分析。结果 119例母亲血25-(OH)D＞30 ng/ml者15例(12.61%),≤30 ng/ml者104例(87.39%);孕期平均每日补充维生素D≥400 U的母亲19例,血25-(OH)D中位数为28.8 ng/ml,每日补充维生素D＜400 U母亲100例,血25-(OH)D中位数为16.1 ng/ml,两组血25-(OH)D差异有统计学意义(P<0.05);在119例婴儿中补充和未补充维生素D组的婴儿血25-(OH)D中位数分别为20.0 ng/ml和9.5 ng/ml,两者差异有统计学意义(P<0.05);婴儿血25-(OH)D与其母亲血清25-(OH)D水平呈正相关(r=0.349,P<0.01)。婴儿血25-(OH)D水平(＞20 ng/ml和≤20 ng/ml)与其出现佝偻病的症状、体征之间无统计学意义。结论 婴儿及其母亲维生素D整体处于不足水平,两者之间维生素D水平存在相关性。婴儿血25-(OH)D＞20 ng/ml并没有降低其发生营养性佝偻病的风险。建议母亲孕期应积极补充维生素D,同时提倡从新生儿一出生即开始补充维生素D,预防婴儿早期营养性佝偻病的发生。     

Components of 25-hydroxyvitamin D in serum of young children in upper midwestern United States.

The relative importance of cholecalciferof (vitamin D3) and ergocalciferol (vitamin D2) in maintaining the vitamin D level in children (1/2 to 6 years old) living in the upper midwestern United States was determined by measurement of total 25-hydroxyvitamin D (25-OH-D), its components, and other indices of calcium homeostasis in serum. In 38 normal children, mean (range) serum total 25-OH-D was 32.8 (less than 5 to 53) ng/ml; in 25 of the 28 sera partitioned, the major component was 25-OH-D3. Significant seasonal variation in serum 25-OH-D3 (mean, range: 35.2, 17 to 51 ng/ml in summer and 15.9, less than 5 to 32 ng/ml in winter) was not accompanied by changes in mean serum 25-OH-D2, calcium, phosphorus, or alkaline phosphatase values. However, individual serum total 25-OH-D values correlated with serum phosphorus values (r = 0.37; P less than 0.05). The proportion of the total represented by 25-OH-D3 varied widely, with a a mean of 83% in summer and 67% in winter. Sources of D3, which include both dermal synthesis and intestinal absorption of D3 added to milk, appear to be more important than sources of D2 in maintaining vitamin D nutrition of young children throughout the year. However, sources of D2 offset the decrease in total 25-OH-D in winter months.     

东海县278名农村中小学生维生素D营养状况分析

目的 了解东海县农村中小学生血清25-(OH)D水平,评估农村中小学生维生素D营养状况。方法采用多阶段分层随机抽样方法,调查278名农村中小学生血清25-(OH)D水平,分析采用t检验、χ²检验等方法。结果278名农村中小学生血清25-(OH)D平均水平为(14.50±0.50)ng/mL,男生为(14.86±0.39)ng/mL,女生为(14.15±0.61)ng/mL,差异无统计学意义(t=0.277,P>0.05);4个年龄组血清25-(OH)D水平差异有统计学意义(F=35.517,P<0.001),其中6～8岁组最高,为(18.19±0.38)ng/mL,12～14岁组最低,为(10.59±0.36)ng/mL。25-(OH)D营养状况正常率仅为13.31%,不足率为24.82%,缺乏率为60.79%,严重缺乏率为1.08%;男女生血清25-(OH)D营养状况差异有统计学意义(χ²=7.450,P<0.05),农村中小学生随着年龄增长维生素D营养状况缺乏率呈上升趋势(χ²_趋势     

Serum 25-hydroxyvitamin D Concentration Significantly Decreases in Patients with COVID-19 Pneumonia during the First 48 Hours after Hospital Admission

It is unclear how ongoing inflammation in Coronavirus Disease 2019 (COVID-19) affects 25-hydroxyvitamin D (25[OH]D) concentration. The objective of our study was to examine serum 25(OH)D levels during COVID-19 pneumonia. Patients were admitted between 1 November and 31 December 2021. Blood samples were taken on admission (day 0) and every 24 h for the subsequent four days (day 1–4). On admission, 59% of patients were 25(OH)D sufficient (>30 ng/mL), and 41% had 25(OH)D inadequacy (<30 ng/mL). A significant fall in mean 25(OH)D concentration from admission to day 2 (first 48 h) was observed (30.7 ng/mL vs. 26.4 ng/mL; p < 0.0001). No subsequent significant change in 25(OH)D concentration was observed between day 2 and 3 (26.4 ng/mL vs. 25.9 ng/mL; p = 0.230) and day 3 and day 4 (25.8 ng/mL vs. 25.9 ng/mL; p = 0.703). The absolute 25(OH)D change between hospital admission and day 4 was 16% (4.8 ng/mL; p < 0.0001). On day 4, the number of patients with 25(OH)D inadequacy increased by 18% (p = 0.018). Therefore, serum 25(OH)D concentration after hospital admission in acutely ill COVID-19 patients should be interpreted with caution. Whether low 25(OH)D in COVID-19 reflects tissue level vitamin D deficiency or represents only a laboratory phenomenon remains to be elucidated in further prospective trials of vitamin D supplementation.     

The Impact of Sample Type on Vitamin D Quantification and Clinical Classification during Pregnancy

Measurement of vitamin D status has significant use in clinical and research settings, including during pregnancy. We aimed to assess the agreement of total 25-hydroxyvitamin D (25(OH)D) concentration, and its three analytes (25-hydroxyvitamin D₃ (25(OH)D₃), 25-hydroxyvitamin D₂ (25(OH)D₂) and Epi-25-hydroxyvitamin D₃ (Epi-25(OH)D₃)), in plasma and serum samples collected during pregnancy, and to examine the proportion of women who change vitamin D status category based on sample type. Matching samples were collected from n = 114 non-fasting women between 12–25 weeks gestation in a clinical trial in Newcastle, Australia. Samples were analysed by liquid chromatography-tandem mass-spectrometry (LC-MS/MS) to quantify total 25(OH)D and its analytes and examined using Bland-Altman plots, Pearson correlation (r), intraclass correlation coefficient and Cohen’s Kappa test. Serum total 25(OH)D ranged from 33.8–169.8 nmol/L and plasma ranged from 28.6–211.2 nmol/L. There was a significant difference for total 25(OH)D based on sample type (measurement bias 7.63 nmol/L for serum vs plasma (95% Confidence Interval (CI) 5.36, 9.90, p ≤ 0.001). The mean difference between serum and plasma concentrations was statistically significant for 25(OH)D₃ (7.38 nmol/L; 95% CI 5.28, 9.48, p ≤ 0.001) and Epi-25(OH)D₃ (0.39 nmol/L; 95% CI 0.14, 0.64, p = 0.014). Of 114 participants, 28% were classified as vitamin D deficient (<50 nmol/L) or insufficient (<75 nmol/L) based on plasma sample and 36% based on serum sample. Nineteen (16.7%) participants changed vitamin D status category based on sample type. 25-hydroxyvitamin D quantification using LC-MS/MS methodology differed significantly between serum and plasma, yielding a higher value in plasma; this influenced vitamin D status based on accepted cut-points, which may have implications in clinical and research settings.