OBJECTIVES:This study aimed to assess the commutability of thyroid-stimulating hormone (TSH) international reference preparations (IRP) among various assays and to elucidate their role in achieving metrological traceability across systems. METHODS:We evaluated the commutability of TSH 3rd IRP 81/565, dissolved in eleven different diluents to achieve two to three different TSH concentrations. The assessment involved 29 serum samples across eight clinical laboratory measurement procedures (CLMP) following the CLSI EP30-A guidelines. Furthermore, 11 different TSH concentrations candidate standard materials prepared from human serum pools (HSPs) were prepared and assigned values from a series of reconstituted IRPs to clarify practical significance of commutable reconstituted IRPs. Two more CLMPs were used to assign values for 11 candidate standard materials using TSH IRP to verify applicability of the diluents. RESULTS:The TSH IRP demonstrated variable commutability in the eleven diluents, with no single diluent achieving commutability across all assay platforms. Notably, we recorded significant biases of approximately 25.5% and -23.2% when utilizing uncommutable matrices(the TSH IRP were not commutable between CLMPs in these matrices) for value assignments of HSPs via CI 1000 and Cobas 601 assays, respectively. Lastly, Harmonized TSH assigned values ranged from 0.191 μIU/mL to 44.985 μIU/mL, with uncertainties varying between 0.039 μIU/mL and 3.523 μIU/mL using 10 CLMP including 13 methods for 11 different TSH concentration candidate standard materials. CONCLUSIONS:The commutability of TSH IRP is crucial for assigning TSH values in clinical practice. The matrices employed for dissolving IRPs present significant challenges in securing commutability, but their influence is vital for TSH multisystem metrological traceability.

Urothelial carcinoma （UC） is a globally prevalent malignancy lacking robust non-invasive biomarkers. Metabolic reprogramming is a recognized cancer hallmark. Untargeted metabolomics enables high-throughput and unbiased analysis of bodily fluids， offering a promising approach for discovering novel biomarkers in UC. This investigation employs untargeted metabolomic profiling to detect novel urinary biomarkers in UC cohorts. The analytical strategy prioritizes tumor-associated metabolic perturbations through pathway-centric characterization of dysregulated biochemical networks. This study systematically characterizes differential metabolites and associated pathway dysregulations in UC cohorts. The approach seeks to establish a reliable metabolic signature with diagnostic and prognostic value. The findings are expected to advance the development of novel clinical tools. UC biomarkers should optimally integrate preclinical identification， treatment response tracking， and precision-tailored interventions. This investigation provides a methodological framework for exploring cancer metabolism in UC. And it offers evidence-based insights to support translational research and precision medicine initiatives in oncology. This study was conducted at Beijing Chao-Yang Hospital， Capital Medical University， between January and December 2020. A total of 60 urine specimens were consecutively collected. They comprised 30 histologically confirmed UC patients and 30 healthy controls with normal urinalysis findings. Clinical data was prospectively collected via structured case report forms. It encompassed baseline demographics， comorbidities， anthropometric and behavioral factors， and UC pathological parameters. All urine samples were collected prior to invasive procedures. And they were labeled， snap-frozen in liquid nitrogen， and stored at -80 ℃ until analysis. Metabolic profiling was performed using a quadrupole-orbitrap high resolution mass spectrometer equipped with a heated electrospray ionization source. Mass spectrometric data processing was performed using Progenesis QI software. Data processing followed the following workflow： raw data import， spectral peak alignment， feature extraction， and deconvolution. The Progenesis QI software generated datasets containing retention time， peak intensity， and mass-to-charge ratios. Multivariate signal decomposition enabled independent resolution of adduct species， including protonated and sodium-adducted ions. Quality control measures included elimination of ion features demonstrating intra-batch coefficient of variation >15% across technical replicates. This rigorous preprocessing protocol ensured removal of unstable signals. And it preserved biologically relevant metabolic features for subsequent multivariate analysis. No statistically significant differences were observed in baseline clinical characteristics between UC and healthy control cohorts （P>0.05）. Untargeted metabolomic profiling was performed using liquid chromatography-tandem mass spectrometry （LC-MS/MS）. Principal component analysis （PCA） revealed no distinct cluster separation between groups. This result was potentially attributed to limited intergroup metabolic variations or restricted sample size. To enhance discriminatory capacity， supervised orthogonal partial least squares-discriminant analysis （OPLS-DA） was implemented for feature selection. This approach effectively addressed variable collinearity while minimizing non-biological noise interference. Differentially expressed metabolites were identified through variable importance in projection scores， fold change and adjusted P-values. Metabolic pathway analysis was conducted， incorporating pathway enrichment analysis. This multi-tiered analytical approach systematically prioritized UC-associated metabolic perturbations while controlling for confounding factors in specimen analysis. Supervised OPLS-DA was employed to identify differential metabolites and associated metabolic pathways. Significant urinary metabolic disparities were detected between UC patients and healthy controls. Alterations were observed in L-Histidine， N-Acetyltryptophan， 5'-methylthioadenosine， N-methylnicotinamide， L-octanoylcarnitine， 3-indolehydracrylic acid， N¹，N¹²-diacetylspermine， pantothenic acid and so on （P<0.05）. Pathway enrichment analysis revealed perturbations spanning amino acid metabolism， nucleotide biosynthesis， vitamin cofactor utilization， and carbohydrate processing. The histidine metabolism pathway demonstrated the highest topological impact. It was followed by the arginine biosynthesis pathway， arginine and proline metabolism pathway， and the tryptophan catabolism pathway. Future validation in larger cohorts and mechanistic studies is warranted to confirm their clinical utility. The aberrant pathways may offer novel biomarkers and therapeutic targets， particularly for patients resistant to conventional therapies.

OBJECTIVES:The impact of seven hemoglobin variants (Hb Q-Thailand, Hb G-Honolulu, Hb Ube-2, Hb New York, Hb J-Bangkok, Hb G-Coushatta, and Hb E) on the outcome of HbA1c was investigated for six methods by comparing with liquid chromatography-tandem mass spectrometry (LC/MS/MS) reference method. METHODS:Twenty-nine normal and 112 variant samples were measured by LC/MS/MS, Sebia Capillarys 3 TERA, Intelligene Biosystems QuanTOF, Premier Hb9210, Arkray HA-8190V, Bio-Rad D-100, and Tosoh G11, then evaluated for correlation, consistency, and mean relative bias among six methods. The lowest biological variation bias of ±2.8 % was an acceptable standard. RESULTS:All methods showed poor correlation and consistency with LC/MS/MS for Hb E. The unacceptable biases were observed for Capillarys 3 TERA (-14.4 to -3.7 % for Hb Q-Thailand, Hb Ube-2, Hb New York, Hb J-Bangkok and Hb E), QuanTOF (-8.3 to -2.9 % for Hb Ube-2, Hb New York and Hb G-Coushatta), Premier Hb9210 (-18.3 to -3.6 % for Hb Q-Thailand, Hb Ube-2, Hb New York, Hb J-Bangkok and Hb E), HA-8190V variant mode (-17.3 to 6.6 % for Hb G-Honolulu, Hb Ube-2, Hb New York, Hb G-Coushatta and Hb E). All variant samples showed larger biases than ±2.8 % comparing HA-8190V fast mode, D-100, and G11 with LC/MS/MS. CONCLUSIONS:The accuracy of different HbA1c methods was influenced by some Hb variants, especially Hb Ube-2 and Hb New York. Thus, laboratories need to choose appropriate methods to measure HbA1c with different Hb variants.

The imbalance of gut microbiota has been confirmed to have a close pathological and physiological correlation with obesity and metabolic syndrome. Ramulus Mori (Sangzhi) Alkaloids (SZ-A) derived from twigs of mulberry was approved by the National Medical Products Administration of China in 2020 for the treatment of type 2 diabetes mellitus. In addition to its hypoglycemic effect, previous studies have confirmed that SZ-A also alleviates high-fat diet-induced obesity and non-alcoholic fatty liver disease and ameliorates obesity-linked adipose tissue metabolism and inflammation, indicating the potential of SZ-A to regulate obesity and metabolic syndrome. However, whether SZ-A can improve obesity and metabolic syndrome by regulating gut microbiota and its metabolism profiles remains unclear. The purpose of this study was to assess the effect of SZ-A on gut microbiota in obese mice and to explore the association among changes in gut microbiota, obesity, and lipid metabolism. The results showed that oral administration of SZ-A could significantly reduce body weight, fat mass, and the level of total cholesterol and low-density lipoprotein in serum in obese mice induced by a high-fat diet. Interestingly, SZ-A also regulated gut microbiota and changed the fecal metabolite composition of obese mice. Compared with the high-fat diet group, the ratio of Firmicutes to Bacteroides changed at the phylum level and the abundance of Bifidobacterium and Akkermansia muciniphila significantly increased at the genus level in the SZ-A group. The gut microbiota of the SZ-A group was reshaped and the relative abundance of microbial genes in bile acid metabolism and fatty acid metabolism were altered, which was consistent with the metabolomics results. Additionally, SZ-A greatly enriched the number of goblet cells and reduced inflammatory colon injury and pro-inflammatory macrophage infiltration induced by a high-fat diet in obese mice. In conclusion, SZ-A can alleviate obesity and metabolic syndrome by improving the gut microbiota and its metabolism profiles of obese mice induced by a high-fat diet.

Background: Recent studies from targeted and untargeted metabolomics have consistently revealed that diet-related metabolites, including carnitine (C0), several species of acylcarnitines (AcyCNs), amino acids, ceramides, and lysophosphatidylcholines (LPCs) may serve as potential multiple myeloma (MM) biomarkers. However, most of these approaches had some intrinsic limitations, namely low reproducibility and compro-mising the accuracy of the results.Objective: This study developed and validated a precise, efficient, and reliable liquid chromatography tandem mass spectrometric (LC-MS/MS) method for measuring these 28 metabolic risk factors in human serum.Design: This method employed isopropanol to extract the metabolites from serum, gradient elution on a hydrophilic interaction liquid chromatographic column (HILIC) for chromatographic separation, and multiple reaction monitor (MRM) mode with positive electrospray ionization (ESI) for mass spectrometric detection.Results: The correlation coefficients of linear response for this method were more than 0.9984. Analytical recoveries ranged from 91.3 to 106.3%, averaging 99.5%. The intra-run and total coefficients of variation were 1.1-5.9% and 2.0-9.6%, respectively. We have simultaneously determined the serological levels of C0, several subclasses of AcyCNs, amino acids, ceramides, and LPCs within 15 min for the first time.Conclusion: The established LC-MS/MS method was accurate, sensitive, efficient, and could be valuable in providing insights into the association between diet patterns and MM disease and added value in further clinical research.

目的 通过回顾2018年至2020年北京市肿瘤标志物室间质量评价(EQA)的结果,分析北京市范围内医学实验室肿瘤标志物的检测现况.方法 每年通过统一配送的方式将10个批号的肿瘤标志物质评物质一次性发放到各参加实验室,每次测定5个批号,然后实验室将其检测结果回报给北京市临床检验中心.对2018年至2020年3年的EQA结果进行统计,分析参加实验室情况,按检测系统进行分组,剔除离群值,以ISO13528方法计算的稳健平均值为靶值,分别计算各组变异系数(CV)等指标,并对由生物学变异推导出的允许不精密度质量规范的应用进行探讨.结果 2018年至2020年的北京市参加肿瘤标志物项目EQA的实验室数目分别为252家、287家和305家,合格实验室数目分别为86.90％、91.67％和92.47％,多数检测项目的合格率和优秀率逐年升高.进口和国产检测系统的组内平均CV均在10％以内.根据生物学变异度导出的允许不精密度质量规范,除CA15-3外,其余所有项目检测系统的组内CV都达到最低的质量规范.CA15-3在三级医院的检测系统的组内CV可达到最低质量规范,而二级和一级医院则未达到.结论 北京市肿瘤标志物项目EQA活动有力提升了北京市范围内该项目整体检测水平.

Objective:To establish a matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF MS) method for the direct detection of serum M protein without antibody enrichment, and to assess its detection performance.Methods:Method establishment. A total of 712 waste serum samples were collected from patients who applied for the M protein identification test in Beijing Chaoyang Hospital affiliated to Capital Medical University. The immunoglobulin light chain was obtained by reduction of IgG and IgA by TCEP, and the detection method was preliminarily determined. The waste serum samples from 20 healthy people were collected to determine the range of mass-to-charge ratios of κ and λ light chain ions. 8 parallel tubes and 8 batches were set up for intra-and inter-batch reproducibility evaluation. 10-fold, 100-fold and 200-fold diluted M protein from 23 positive samples were detected by established MALDI-TOF MS method, and its sensitivity was evaluated. 3 methods of IFE, SPE and MALDI-TOF MS were used to detect M protein simultaneously, and the coincidence rate between MALDI-TOF MS and IFE and SPE was calculated.Results:The repeatability within and between batches was 100%, respectively. The original, 10-, 100-and 200-fold dilutions of 23 M protein-positive samples were determined, and the detection limit of MALDI-TOF MS for M protein was 0.06-0.18 g/L. IFE as the gold standard, the overall coincidence rates of SPE and MALDI-TOF MS were 85.9% and 92.3%, respectively, and the positive coincidence rates of SPE and MALDI-TOF MS were 72.8% and 99.7%, respectively, of the 712 samples. Among the different types of M-proteins, MALDI-TOF-MS agreed 100% with IFE M-protein results for IgA, IgD, IgM, free light chain type and biclonal group, while the agreements of SPE for IgM, IgA and free light chain samples were only 66.7%, 58% and 19.5%, respectively. One positive sample in the IgG group was not detected by MALDI-TOF MS. 23 M-proteins positive samples were diluted by original, 10, 100 and 200 times to access the sensitivity of MALDI-TOF MS method. The coincidence rate of MALDI-TOF MS was 100% and IFE was 96% at 10-fold dilution. The coincidence rate of IFE was 28% and 23% of MALDI-TOF MS at 100-fold and 200-fold dilution, respectively.Conclusions:A MALDI-TOF MS method for the detection of serum M-proteins was successfully established. This method has the advantages of high detection throughput, fast speed, good sensitivity, specificity and coincidence rate.

Background The atherosclerotic coronary artery disease (CAD) risk assessment based on conventional risk factors have only moderate performance, and residual risks still exist. Thus, we reported here a cohort study that aims to identify and validate the new biosignatures (especially the metabolomics, lifestyle biomarkers and biological age), and elucidate their predictive effect on CAD and subsequent cardiovascular events. Methods This prospective, single-center, cohort study commenced in March 2017 and seeks to examine patients undergoing coronary angiography (CAG) at the Beijing Hospital. Patients’ baseline demographic and medical history data are captured by questionnaires. Blood samples are taken before CAG for clinical laboratory tests and metabolomics analyses. Traditional CAD risk factors are analyzed by routine assays. CAD-related metabolites from different metabolic pathways and lifestyle biomarkers are measured by liquid chromatography-tandem mass spectrometry methods. Biological ages are calculated based on the laboratory and metabolomics data. The enrolled patients attend annual follow-up examinations for 10 years. The primary end points are the composite end points of major adverse cardiovascular events, including death from any cause, non-fatal myocardial infarction, and non-fatal stroke. Quality management and control are carried out through the entire research process, including standardized baseline and follow-up investigation, intra- and inter-run quality controls for laboratory measurements, etc. Results Baseline data of the enrolled 2,970 patients from 2017 to 2020 were collected and are presented in this article. Among them, there were more males (62.5%) than females, and the patients tended to be old and overweight. The percentages of diagnosed hypertension and diabetes were 67.3% and 35.2%, respectively. A total of 8.5% had a family history of premature CAD. Their lipid profiles were within the normal range, probably due to the use of statins. Conclusions This study has successfully initiated an investigation into the roles of new biosignatures in predicting CAD among Chinese Han patients undergoing CAG. To the best of our knowledge, this cohort is the first study systematically focusing on the association of lifestyle biomarkers and biological age with CAD risk. Findings from this study will provide biomarkers to discriminate the presence of CAD and to predict subsequent cardiovascular events.

Glycated albumin (GA) in human serum is tested clinically as a short-term indicator for glucose monitoring. Here, we evaluated a candidate serum reference material (RM) at three different GA concentrations to help standardize serum GA measurements. Both albumin and GA were quantitatively determined using isotope-dilution liquid chromatography/tandem mass spectrometry with lysine-4,4,5,5-D4·2HCl (D4-lysine) and Nε-l3C6-(l-deoxy-d-fructose-1-yl)-l-lysine (13C6-DOF-lysine) as internal standards and lysine and synthetic DOF-lysine as calibration standards. The method was evaluated with the RM, JCCRM611-1, from the Reference Material Institute for Clinical Chemistry Standards. The homogeneity and stability of the candidate RMs were examined using a commercial biochemical analyzer. Fifteen units were randomly selected, and statistical analysis showed no inhomogeneity. The candidate RMs were stable for at least 6 months at -80 °C. The coefficients of variation (CVs) for the JCCRM611-1 RM ranged from 3.2% to 2.3%, and the biases ranged from 4.12% to -1.84%. GA was tested at low, medium, and high concentrations, which were quantified as 249.53 ± 13.29, 408.02 ± 11.70, and 637.22 ± 17.03 mmol/mol, respectively. The overall CVs ranged from 0.99% to 2.51%. The candidate RMs can potentially be used to develop a traceability chain to improve the accuracy of GA measurements.

BackgroundGlycated hemoglobin (HbA1c) is measured to monitor patients with diabetes. However, the measurement results can vary according to the analysis method and presence of variant hemoglobin. Thus, we compared HbA1c results between liquid chromatography-tandem mass spectrometry (LC-MS/MS) as the reference method and matrix assisted laser desorption/ionization time of flight mass spectrometry (MALDI-TOF MS).Methods%HbA1c were measured using the two methods in 45 non-variant and 73 heterozygous variant samples. Precision was calculated; the results were compared using Passing-Bablok regression and the concordance correlation coefficient (CCC). The average bias between methods was compared with the lowest bias of 2.3% for biological variation.ResultsThe precision of the two methods was < 2%. The R2 for the non-variant samples were 0.986 and the CCC was 0.99. Based on α- and β-chain, the variant samples were divided into four groups: α-chain, α-chain negligible, β-chain, and β-chain negligible variants. The R2 between the two methods of the four groups were ＞0.95; However, the average biases of α-chain and β-chain variants were above the minimum bias.ConclusionLC-MS/MS and MALDI-TOF MS had good comparability in the measurement of HbA1c in non-variant samples, but the existence of variant hemoglobin caused discrepancies.

Objective:To establish the sex-, age-and season-specific (month) reference intervals (RI) for thyroid stimulating hormone (TSH) measurement by big data and indirect method in adults.Methods:TSH data of anonymous patients were collected from Beijing Chaoyang Hospital Affiliated to Capital Medical University in 2016, the data were selected and outliers were removed. Indirect methods (Hoffmann method and Bhattacharya method) were used to calculate TSH reference intervals of whole population, different genders, ages and seasons (months). TSH RI from two indirect methods of total population, selected population, physical examination population was compared with RI from reagent instruction according to reference change value ( RCV) based on biological variability. Results:A total of 61 599 records were obtained from 90 699 records including 18 776 males and 42 823 females. The TSH RI were obtained by Hoffmann method: the whole population, 0.59-5.59 μIU/ml (1 μIU/ml=1 mIU/L), male, 0.53-5.16 μIU/ml, female, 0.59-6.11 μIU/ml. The upper limits of TSH RI were higher with age and in winter (January): 18-30 years old, 0.62-5.57 μIU/ml, 71-80 years old, 0.49-6.45 μIU/ml; January, 0.59-6.40 μIU/ml, August, 0.60-5.56 μIU/ml; The RI of TSH by Bhattacharya method: the whole population, 0.58-5.80 μIU/ml, male, 0.55-5.02 μIU/ml, female, 0.62-6.21 μIU/ml. The upper limits of TSH RI were also higher with age and in winter (January): 18-30 years old, 0.65-5.67 μIU/ml, 71-80 years old, 0.46-5.99 μIU/ml, January: 0.61-6.52 μIU/ml, August: 0.61-5.69 μIU/ml. Compared to RI from reagent instruction, the differences of TSH RI from two indirect methods of total population, selected population, physical examination population were acceptable.Conclusions:TSH RI was established by indirect method. With the increase of age and winter, the upper limit of TSH reference interval tends to increase.

Recent studies have found that carnitine and acylcarnitines (AcyCNs) are potential biomarkers for many metabolic diseases, including inherited disorders, diabetes and coronary atherosclerotic artery disease (CAD). Here we presented and validated a method for measurement of free carnitine and twelve AcyCNs in human serum by using electrospray ionization tandem mass spectrometry (ESI-MS/MS). Serum samples were mixed with isotopic labeled internal standards and extracted with isopropanol. Carnitine and AcyCNs were separated within 5min by isocratic elution on a hydrophilic interaction liquid chromatographic column (HILIC) and detected with electrospray ionization (ESI) in positive ion mode with multiple reaction monitor (MRM) mode. This method was linear in response with correlation coefficients higher than 0.999. Analytical recoveries were 89.4%-105.4% with an average of 98.7%. The intra-run and total imprecisions were 0.9-4.7% and 1.5-14.1%, respectively. Stability tests showed that all the compounds were stable in serum for at least 6 month at 80 degrees C, but unstable when stored at room temperature (RM) and 4 degrees C. Serum carnitine and AcyCNs concentrations of 472 apparently healthy subjects were analyzed. Significant associations between the metabolites and traditional CAD risk factors were observed. The established HILIC-ESI-MS/MS method was simple, precise, and sensitive and may be used as an efficient tool in CAD risk assessment and research. (C) 2019 Elsevier B.V. All rights reserved.

目的应用质谱多反应监测扫描（MRM）技术准确测定糖尿病患者体内糖化血红蛋白的水平。方法在国际临床化学和实验室医学联盟（IFCC）推荐的质谱法测定糖化血红蛋白参考方法的基础上,利用IFCC参考实验室一级校准物质绘制标准曲线,使用质谱单离子检测扫描（SIM）和MRM 2种模式测定IFCC参考实验室国际比对样本及临床患者标本,计算2种方法的均值、精密度和偏倚,评价质谱MRM方法测定糖化血红蛋白的优势。结果在SIM和MRM 2种监测模式下,均以峰面积为计算依据,横坐标为峰面积比值,纵坐标为浓度CONC比值,绘制标准曲线,在给定的浓度范围内,2种检测方法r~2分别为0.998 8和0.999 2;测定IFCC参考实验室国际比对样本中糖化血红蛋白的水平,SIM模式下,精密度为0.77%～1.81%,偏倚为-0.35～0.30mmol/mol;MRM模式下,精密度为0.81%～1.84%,偏倚为-0.20～0.40mmol/mol。结论在质谱法测定血液样本中糖化血红蛋白水平时,应用MRM监测模式可以获得与SIM模式一致的结果,检测值和精密度等监测结果均符合IFCC参考实验室国际比对要求,同时灵敏度和信噪比进一步提升,抗干扰能力更好,应用前景广阔。

Background: Hyperglycemia has become a major health problem worldwide. We investigated the associations of serum metabolite levels with hyperglycemia (impaired fasting glucose/diabetes) and traditional risk factors for metabolic disease. Methods: A total of 563 Chinese adults were categorized into hyperglycemia and control groups. Associations of serum metabolites, including branched-chain amino acids (BCAAs), aromatic amino acids (AAAs), glutamine (Gln), glutamic acid (Glu), Gln/Glu ratio, 25-hydroxyvitamin D, and lysophosphatidylcholine (LPC), with hyperglycemia and traditional risk factors of metabolic disease were investigated using our targeted metabolomics method. Results: Participants with impaired fasting glucose or diabetes exhibited markedly lower levels of Gln/Glu and unsaturated LPC and higher levels of Glu and BCAAs. Gln/Glu ratio, unsaturated LPC, and 25-hydroxyvitamin D were positively correlated with protective factors, while saturated LPC, BCAAs, AAAs, and Glu revealed close correlations with traditional risk factors. In the logistic regression, low Gln/Glu ratio and high BCAA level were independent risk factors for hyperglycemia; the odds ratios (95% confidence interval) of the highest quartile compared with the lowest quartile were 0.499(0.274-0.910) and 2.588 (1.313-5.102) (P < 0.05), respectively. Conclusions: Gln/Glu ratio, BCAAs, and LPC were significantly related to hyperglycemia development and risk factors for metabolic disease.

Diagnosis and treatment of diabetes mellitus depend on accurate monitor of blood glucose of laboratory.Glycated albumin,the short-term indicator of blood glucose control, has special advantage and role in the monitor of diabetes mellitus and has been payed more and more attention.The standardization work of determination of glycated albumin at home and abroad is still in the primary stage at present.The consistency and accuracy of measurement results for glycated albumin is needed to be solved urgently.

Objective To prepare the serum reference materials for total thyroxine .Methods Individual blood samples were collected from 13 healthy donors (7 males and 6 females) aged from 20 to 50 years old, and the sera were separated and mixed into 4 serum pools according to the concentration of thyroxine.The materials were tested for homogeneity and stability using routine methods .The method of isotope dilution liquid chromatography tandem mass spectrometry ( ID-LC/MS/MS) was used to determine the concentration of thyroxine .The candidate reference materials were also measured by four conventional methods to analyze the commutability of the materials .Results It showed that the four candidate reference materials were homogeneous and commutable in four conventional methods and they were tested to be stable for at least 1 year at -70 ℃using the isochronous stability study .The certified values ( reference value ± expanded uncertainty ,nmol/L) were:75.9 ±1.8,105.3 ±2.2,114.7 ±2.1 and 187.4 ±2.9.Conclusions Certified reference materials for serum thyroxine have been prepared .These materials have been approved to be the Certificate Reference Materials of GBW 09127,GBW 09128,GBW 09129 and GBW 09130.

目的:了解北京地区人群维生素D含量情况,研究人血清25-羟基维生素D水平与多种心血管病危险因素的关系,为早期预防心血管疾病提供数据支持.方法:采用横断面调查方法,收集北京地区体检人群580例.采用同位素稀释液相色谱串联质谱法测定血清25-羟基维生素D3和25-羟基维生素D2,用以评价体内维生素D状态;同时测定传统心血管病危险因素以及胆固醇酯脂肪酸类(CE-FA)、支链(BCAA)及芳香族氨基酸类(AAA)、溶血卵磷脂类(LPC)等新发现的心血管病潜在危险因素,分析血清25-羟基维生素D水平与这些指标的关系.结果:580例体检人群血清总25-羟基维生素D浓度为(21.57±7.83) μg/L,参考区间(2.5％～97.5％分位数)9.41～ 38.32 μg/L;男性(22.68±7.60)μg/L)显著高于女性(20.18 ±7.90) μg/L) (P ＜0.001).研究对象中维生素D严重缺乏、缺乏、不足和充足所占比例分别为3.3％、42.8％、39.3％及14.6％.非参数相关分析表明校正年龄、性别后总25-羟基维生素D水平与HDL-C、apoAI、不饱和LPC、Omega-3型CEFA等心血管保护因素均呈显著正相关,同时与apoB、超敏C反应蛋白、血浆致动脉粥样硬化指数、BCAA、AAA、饱和CEFA等心血管病危险因素均呈显著负相关.结论:血清25-羟基维生素D可能是心血管保护因素,其对预防和改善心血管疾病具有潜在积极作用.

Accurate and precise glucose measurements are requisite for ensuring appropriate diagnosis and management of diseases related to hyperglycemia or hypoglycemia. It is necessary to have a higher order method to provide an accuracy base to which routine methods can be compared. We developed and evaluated a highly reliable measurement procedure based on isotope dilution liquid chromatography–tandem mass spectrometry (ID LC-MS/MS) with a simple one-step derivatization. An appropriate amount of serum was accurately weighed and spiked with an isotope-labeled internal standard. After protein precipitation, the supernatant was reacted with 1-phenyl-3-methyl-5-pyrazolone for chemical structural transformation. The glucose derivatives were analyzed with LC-MS/MS in positive electrospray ionization mode. The within-run and total CVs ranged from 0.28 to 0.42 % and from 0.42 to 0.76 %, respectively, for a concentration range of 1.691 to 15.676 mmol/L. A regression comparison of the presented method to an existing RMP based on ID GC-MS showed agreement with no statistical difference (Y = 0.9985X-0.008; 95 % CI for the slope, 0.9966 to 1.001; 95 % CI for the intercept, −0.012 to 0.019). The structural analogs of glucose with a molecular mass of 180 were tested, and no significant interference effect was found. The limit of quantification was estimated to 0.8 ng glucose in absolute amount. This method is accurate, simple, and can serve as a candidate reference measurement procedure (RMP) in the establishment of a serum glucose reference system.

Objective To investigate the association between serum 25-hydroxyvitamin D (25-OH D)and subclinical atherosclerosis in elderly people.Methods The cross-sectional study was undertaken on 186 elderly people participating in the health examination in Beijing Hospital.Their venous blood samples were collected.The medical history and carotid intima-media thickness(clMT) in each volunteer were obtained by questionnaire and the ultrasound B-mode images on bilateral carotid artery,respectively.The serum vitamin D status of participants was evaluated based on serum 25-OH D concentration which was determined by liquid chromatography-tandem mass spectrometry method.The association of serum 25-OH D with clMT as the marker of subclinical atherosclerosis was analyzed.Results The statistical distribution of total serum 25-OH D in the elderly individuals tended to be leptokurtic and skewed,giving a median and reference intervals(2.5th to 97.5th percentile)of 22.76 and 9.74～40.33 μg/L.The total serum 25-OH D was significantly higher in males[23.78(19.00～ 28.81)μg/L]than in females[20.98(17.24～ 26.52)μg/L] (Z=-2.059,P=0.040).Compared with the control group,the subclinical atherosclerosis group (clMT＞1.0 mm)showed the significantly decreased 25-OH D levels.Total serum 25-OH D concentrations were negatively correlated with cIMT (r=-0.178,P=0.016).The multiple logistic regression analysis showed that The 25-OH D levels and sex were the independent risk factors for subclinical atherosclerosis.After adjusting for the confounding factors,the odds ratio of serum 25-OH D was 0.221 (OR =0.221,95％ CI:0.076 ～ 0.642)for the highest quartile versus the lowest quartile.Conclusion The decreased level of 25-OH D may increase risks for subclinical atherosclerosis.

Recent observations from metabonomic studies have consistently found that branched-chain amino acids (BCAAs), aromatic amino acids (AAAs), glutamine (Gin), glutamic acid (Glu), Gln/Glu ratio, carnitine, and several species of acylcarnitines and lysophosphatidylcholines (LPCs) are possible risk factors for metabolic diseases such as diabetes mellitus (DM) and cardiovascular diseases (CVD). We described here a simple and reliable method for simultaneous quantification of these metabolic risk factors by liquid chromatography tandem mass spectrometry (LC-MS/MS). Serum samples were extracted with isopropanol, and the extracted metabolites were separated by hydrophilic interaction liquid chromatography (HILIC) and detected with electrospary ionization (ESI) inpositive ion mode with multiple reaction monitor (MRM) mode. All the metabolites were effectively separated within 5.5 min. Analytical recoveries were in the range of 92.8-106.9%, with an average of 100.6%. The intra-run and total imprecisions for the measurement of these metabolites were 1.2-3.8% and 1.5-7.4%, respectively. Serum concentrations of the metabolites were analyzed in 123 apparently healthy volunteers. Significant associations between the metabolites and traditional CVD risk factors were observed. The newly developed LC-MS/MS method was simple, precise, and accurate and can be used as an efficient tool in CVD research and studies. (C) 2015 Elsevier B.V. All rights reserved.