Establishing and evaluating a robust method based on LC-MS/MS for simultaneous determination of Aβ1-42,Aβ1-40 and A β1-38 in cerebrospinal fluid / 中华检验医学杂志

Objective:To establish and validate an LC-MS/MS method for simultaneous determination of Aβ 1-42, Aβ 1-40, and Aβ 1-38 in cerebrospinal fluid. Additionally, the consistency between this method and three mainstream detection methods was evaluated.Methods:This study involved method establishment, validation, and consistency evaluation. The N15 labeled β-amyloid protein was used as the internal standard. Extraction was performed using Waters MCX 96-wells solid phase extraction plate, and the eluent was collected to QuanRecovery MaxPeak 700 μl plate. At the positive ion mode, the multi-reaction ion monitoring mode based on electric spray ionization is chosen for the determination of CSF Aβ 1-42, Aβ 1-40, and Aβ 1-38. Referring to the CLSI C62-A and EP-15A3 guidelines, the method is evaluated and verified, including quantitation of limit (LOQ), linearity, recovery, precision, and accuracy. In addition, a total of 57 clinical residual CSF samples were collected and the concentrations of Aβ 1-42 and Aβ 1-40 were determined based on manual INNOTEST ELISA assay and Lumipulse G and Roche Elecsys fully automated biochemical analyzers. The comparison analysis and deviation evaluation were conducted by passing-bablok and Bland Altman methods.Results:The analysis time of this method is 8 min, and the LOQ of Aβ 1-42, Aβ1-40 and Aβ1-38 is 0.1 ng/ml, 0.5 ng/ml, and 0.1 ng/ml, respectively, and the linear range can meet the needs of clinical detection. Respectively, the recovery is 86.2%-93.8%, 100.9%-103.9% and 103.3%-107.1%; the total imprecision is 4.7%-7.4%, 3.5%-4.6% and 5.2%-10.9%. The measured values of Aβ 1-42 certified reference materials are all within the allowable uncertainty requirements. Moreover, the carryover rate of three analytes was all≤0.11%. In addition, the correlations of Aβ 1-42 and Aβ1-40 in CSF between this LC-MS/MS method and the INNOTEST ELISA method, Lumipulse G and Roche Elecsys fully automated biochemical analyzers were all deemed good, with correlation coefficient (r) ranging from 0.920 to 0.970. However, the measured values between the four methods were remarkably different.Conclusion:We established and validated a robust method based on LC-MS/MS technology for simultaneous determination of Aβ 1-42, Aβ 1-40, and Aβ 1-38 in CSF. The method is accurate, simple, and suitable for clinical measurements. However, despite good correlations, there were substantial differences in the measurement results of Aβ 1-42 and Aβ 1-40 among different analytical platforms, indicating the need for further promotion of harmonization and standardization processes for AD classic biomarkers.

Performance evaluation of automated magnetic beads extraction method for the measurement of catecholamine metabolites analyzed by liquid chromatography tandem mass spectrometry / 中华检验医学杂志

Objective:To evaluate the performance of magnetic beads extraction method (MGE) for the measurement of catecholamine metabolites by liquid chromatography tandem mass spectrometry.Methods:This is a methodological evaluation study. The linearity, limit of quantitation, recovery, precision, and matrix effect of catecholamine metabolites 3-methoxyepinephrine (MN), 3-methoxynorepinephrine (NMN) and 3-methoxytyramine (3-MT) extracted by MGE method were evaluated according to CLSI C62-A. Consensus of method development and validation of liquid chromatography-tandem mass spectrometry in clinical laboratories and other guidelines, 132 clinical residual plasma samples were collected and extracted by automated MGE and traditional solid phase extraction (SPE) method to compare the harmonization of the two extraction methods.Results:The linearity of MN, NMN and 3-MT extracted by automated MGE was>0.99, and the LOQ for MN, NMN and 3-MT were 0.033 5 nmol/L, 0.054 7 nmol/L and 0.011 0 nmol/L, respectively. The repeatability of MN, NMN and 3-MT were 1.3%-5.1%, 2.2%-5.6% and 1.7%-7.1%, respectively. The total imprecision in the laboratory were 1.5%-8.2%, 2.2%-7.7%, 2.1%-11.2%. Although the absolute recovery is low, the average relative recoveries of MN, NMN and 3-MT were 91.5%-108.5%, 92.0%-108.6%, and 89.3%-104.1%, respectively, and the percentage deviation from the expected concentration was within 15%. After isotope internal standard correction, the relative matrix effect is close to 100%, which can compensate for the potential matrix effect. The results of MGE and SPE of MN, NMN and 3-MT showeda good correlation (correlation coefficient r>0.99). The average relative deviations of MN, NMN and 3-MT were 0.2%, -1.4% and 1.0%, respectively. Conclusion:The automatic MGE method hasa good performance in extracting catecholamine metabolites, and is expected to be used in high-throughput analysis of samples in clinical in the future.

Case report of pseudoelevated serum testosterone in women and literature review / 中华检验医学杂志

Objective:The characteristics of women with false elevated testosterone were analyze and the literature was reviewed to provide reference for clinical laboratory identification of false elevated testosterone.Methods:The characteristics of three patients with false elevated testosterone in Peking Union Medical College Hospital were analyzed retrospectively, and the results of different detection platforms and methods for the determination of testosterone levels were compared. International and domestic literatures related to false elevation of testosterone and detection methods of testosterone were searched for a comprehensive analysis from PUBMED and CNKI.Results:The levels of testosterone in 3 female patients were elevated by immunoassay and normal by mass spectrometry. They were excluded from the diagnosis of hyperandrogenemia. A total of 38 literatures related to testosterone detection were retrieved, of which 9 case reports of pseudohyperandrogenemia, among which 12 cases of pseudohyperandrogenemia were reported in 2 domestic literatures in 2021. All cases were confirmed by liquid chromatography-tandem mass spectrometry (LC-MS/MS). Previous studies have clearly indicated that the result of routine immunoassay in clinical laboratory for the determination of female testosterone have poor correlation with the results of LC-MS/MS, with varying degrees of deviation.Conclusions:Immunoassay tests for female testosterone is susceptible to interference and lead to elevated false results. It is suggested that clinical laboratories evaluate the detection methods used and establish a identification program, and confirm samples with suspected pseudoelevated testosterone elevation using other immune platforms or LC-MS/MS.

Reference Intervals for Thyroid-Associated Hormones and the Prevalence of Thyroid Diseases in the Chinese Population

Background@#Thyroid diseases are highly prevalent worldwide, but their diagnosis remains a challenge. We established reference intervals (RIs) for thyroid-associated hormones and evaluated the prevalence of thyroid diseases in China. @*Methods@#After excluding outliers based on the results of ultrasound screening, thyroid antibody tests, and the Tukey method, the medical records of 20,303 euthyroid adults, who visited the Department of Health Care at Peking Union Medical College Hospital from January 2014 to December 2018, were analyzed. Thyroid-associated hormones were measured by the Siemens Advia Centaur XP analyzer. The RIs for thyroid-associated hormones were calculated according to the CLSI C28-A3 guidelines, and were compared with the RIs provided by Siemens. The prevalence of thyroid diseases over the five years was evaluated and compared using the chi-square test. @*Results@#The RIs for thyroid stimulating hormone (TSH), free thyroxine (FT4), free triiodothyronine (FT3), total thyroxine (TT4), and total triiodothyronine (TT3) were 0.71–4.92 mIU/L, 12.2–20.1 pmol/L, 3.9–6.0 pmol/L, 65.6–135.1 nmol/L, and 1.2–2.2 nmol/L, respectively. The RIs of all hormones except TT4 differed significantly between males and females. The RIs of TSH increased with increasing age. The prevalence of overt hypothyroidism, overt hyperthyroidism, subclinical hypothyroidism, and subclinical hyperthyroidism was 0.5% and 0.8%, 0.2% and 0.6%, 3.8% and 6.1%, and 3.3% and 4.7% in males and females, respectively, which differed from those provided by Siemens. @*Conclusions@#Sex-specific RIs were established for thyroid-associated hormones, and the prevalence of thyroid diseases was determined in the Chinese population.

Clinical application and research progress of inductively coupled plasma mass spectrometry technology / 中华检验医学杂志

Inductively coupled plasma mass spectrometry (ICP-MS) technology has the advantages of high sensitivity, wide linear range, good stability, and simple operation, which plays important roles in multi-element quantitative analysis, isotope analysis, speciation analysis and so on. ICP-MS technology can accurately and simultaneously determinate trace elements and toxic elements in different types of human samples, which is important for the diagnosis and treatment of clinical related diseases. Its combination with laser ablation, chromatography and other injection and/or separation technology makes its application much wider.

Analysis of the oxidative products of DNA(8-oxo Gsn) and RNA(8-oxo dGsn) in patients with essential hypertension / 中华检验医学杂志

Objective:Analysis of the oxidative products of DNA and RNA in patients with hypertension by determination of 8-oxo Gsn and 8-oxo dGsn, respectively.Methods:This is an observational study. During August and December, 2018, 139 hypertension patients without other chronic diseases with an average age of (49.6±12.4) years old, and 139 apparently healthy volunteers without hypertension with an average age of (48.5±11.7) years old were recruited. Fasting morning urine were collected. The oxidative products of DNA: 8-oxo Gsn and the products of RNA: 8-oxo dGsn were analyzed using liquid chromatography tandem mass spectrometry. Urine Cr(U-Cr), and other serum biomarkers such as ALT, Cr, UA, Glu, TG, TC were analyzed using automatic biochemical analyzers.Results:of 8-oxo Gsn and 8-oxo dGsn were presented as median(quartile). Statistical analysis was performed using SPSS 22.0 and GraphPad Prism 5. Nonparametric test was used to compare the difference of 8-oxo Gsn and 8-oxo dGsn between the hypertension patients and the healthy controls. Results The DNA and RNA oxidative products of 8-oxo Gsn and 8-oxo dGsn in patients with hypertension and their U-Cr-corrected 8-oxo Gsn/U-Cr and 8-oxo dGsn/U-Cr were 14.38(10.39-19.91)ng/ml, 12.97(7.92-18.96)ng/ml, 1.10(0.88-1.38)μg/μmol and 0.96(0.75-1.30) μg/μmol, respectively, which were significantly higher than those in the healthy controls: 11.95(7.52-18.01) ng/ml, 10.12(6.42-15.04) ng/ml, 0.86(0.59-1.21) μg/μmol and 0.72(0.50-1.02) μg/μmol, respectively. After grouped by sex, 8-oxo Gsn in males, 8-oxo Gsn and 8-oxo dGsn in females showed no significant difference between patients with hypertension and healthy controls, however, after U-Cr correction, both males′ and females′ 8-oxo Gsn/U-Cr and 8-oxo dGsn/U-Cr in patients with hypertension were higher than that in the healthy controls.Conclusion:The oxidative products of DNA and RNA in patients with hypertension were significantly higher than that in healthy controls.

Maternal iron status in the first trimester is associated with gestational diabetes mellitus and macrosomia / 中华健康管理学杂志

Objective:To evaluate the association of maternal nutrition status in the first trimester with gestational diabetes mellitus (GDM) and macrosomia.Methods:378 pregnant women who took prenatal care in Shunyi Women′s and Children′s Hospital of Beijing Children′s Hospital were enrolled in the study. Blood samples were collected at first prenatal visit (<12 gestation weeks) to measure the level of hemoglobin and iron status indexes including serum iron, ferritin, transferrin, total iron binding capacity, iron saturation, transferrin saturation. The incidence of GDM and macrosomia were collected and Logistic regression was used to evaluate the associations of maternal nutrients status in the first trimester with GDM and macrosomia.Results:The incidence rate of GDM was16.9%,the incidence of anemia and iron deficiency in the first trimester were2.4% and 2.5%, respectively. After adjustment for variables such as maternal age, pre-pregnancy BMI, family history of diabetes, and parity, Logistic regression showed that in the first trimester, iron saturation>50% ( OR=0.238, 95% CI 0.068-0.831), transferrin saturation>50% ( OR=0.08, 95% CI 0.010-0.677) were protective factors of GDM; iron saturation 25%-50% ( OR=0.361, 95% CI 0.143-0.908); transferrin saturation 25%-50% ( OR=0.383, 95% CI 0.165-0.891); ferritin>30 ng/ml ( OR=0.418, 95% CI0.186-0.939) were protective factors of macrosomia. Conclusion:Maternal iron status in the first trimester might be associated with GDM and macrosomia. Thus, maternal iron status assessment in the first trimester is necessary.

Consistency evaluation of thyroid stimulating hormone results from 4 chemiluminescence assays / 临床检验杂志

Objective@#To compare the consistency of thyroid stimulating hormone (TSH) results from four chemiluminescence assays. @*Methods@#A total of 102 fresh serum samples from Peking Union Medical College Hospital during March 2018 and April 2018 were collected for precision evaluation and methodological comparison referring to CLSI EP15-A2 and EP9-A2 protocols. The levels of serum TSH were detected by Abbott i2000 (system A), Beckman DXI800 (system B), Siemens ADVIA Centaur XP (system C) and Roche e601 (system D) automatic chemiluminescence analyzers and their matching reagents, respectively. The obtained results were compared with the passing-bablok and Bland Altman methods. Taking 0.27 μIU/mL and 5.33 μIU/mL as the medical decision level, the expected bias of each detection system was compared. @*Results@#The precisions of systems A,B,C and D were 1.7%-3.3%， 2.3%- 3.9%，0.7%-2.3% and 0.6%-1.5%,respectively. The median (P 25,P 75) of TSH concentrations detected by systems A,B,C and D were 1.898 (0.518,4.809)μIU/mL, 2.819 (0.719,7.020)μIU/mL,2.502 (0.692,6.888)μIU/mL and 3.105 (0.886, 7.905)μIU/mL, respectively. The coefficients of determination (R 2 ) of regression equation were above 0.975 for 4 detection systems. The correlation coefficients (r), intercepts and slopes of 4 detection systems were 0.993 5-0.997 1, 0-0.06 and 0.59-1.15, respectively, and systems B and C had the best correlations with 1.02 of slope and 0 of intercept. The deviation plot showed that the bias% of 4 detection systems was between -48.1% and 17.3%. Among them, systems A and D had the largest bias, while systems B and C had the lowest bias. The expected bias of 4 detection systems at the medical decision level was -40.7%-37.2%. @*Conclusion@#The consistency between Beckman and Siemens TSH detection systems is good, while those of Roche and Abbott TSH detection systems are different from the other two.

Comparison of Six Automated Immunoassays With Isotope-Diluted Liquid Chromatography-Tandem Mass Spectrometry for Total Thyroxine Measurement

BACKGROUND: Accurate serum total thyroxine (TT4) measurement is important for thyroid disorder diagnosis and management. We compared the performance of six automated immunoassays with that of isotope-diluted liquid chromatography-tandem mass spectrometry (ID-LC-MS/MS) as the reference method. We also evaluated the correlation of thyroid stimulating hormone (TSH) with TT4 measured by ID-LC-MS/MS and immunoassays. METHODS: Serum was collected from 156 patients between October 2015 and January 2016. TT4 was measured by immunoassays from Abbott (Architect), Siemens (ADVIA Centaur XP), Roche (E601), Beckman-Coulter (Dxi800), Autobio (Autolumo A2000), and Mindray (CL-1000i), and by ID-LC-MS/MS. Results were analyzed using Passing-Bablok regression and Bland-Altman plots. Minimum requirements based on biological variation were as follows: a mean bias of ≤4.5% and total imprecision (CV) of ≤3.7%. RESULTS: All immunoassays showed a correlation >0.945 with ID-LC-MS/MS; however, the slope of the Passing-Bablok regression line varied from 0.886 (Mindray) to 1.23 (Siemens) and the intercept from −12.8 (Siemens) to 4.61 (Mindray). Only Autobio, Beckman-Coulter, and Roche included the value of one in the 95% confidence interval for slope. The mean bias ranged from −10.8% (Abbott) to 9.0% (Siemens), with the lowest value noted for Roche (3.5%) and the highest for Abbott (−10.8%). Only Abbott and Roche showed within-run and total CV ≤3.7%. CONCLUSIONS: Though all immunoassays correlated strongly with ID-LC-MS/MS, most did not meet the minimum clinical requirement. Laboratories and immunoassay manufacturers must be aware of these limitations.

Survey for variation of prevalence of hyperuricemia and its correlations with blood glucose and lipid in healthy adults receiv-ing physical examination at Peking Union Medical College Hospital from 2012 to 2017 / 临床检验杂志

Objective To investigate the changes of prevalence of hyperuricemia ( HUA) and its correlations with blood glucose and lipid in healthy adults receiving physical examination at Peking Union Medical College Hospital (PUMCH) from 2012 to 2017. Meth-ods An observational approach was adopted for the data analysis.The test results of uric acid (UA),fasting blood glucose (FBG),to-tal cholesterol (TC),triacylglycerol (TG),low density lipoprotein cholesterol (LDL-C),high density lipoprotein cholesterol (HDL-C), creatinine (Cr) and Urea of 399 089 cases (206 881 males and 192 208 females) at PUMCH from January 2012 to December 2017 were collected and statistically analyzed.Results The total prevalence of HUA was 17.4% in which the prevalence of males was signif-icantly higher than that of females (25.6% vs 8.5%,χ2＝20 234.850,P＜0.01).During the years of 2012 to 2017,the prevalence of HUA was 26.5%,24.7%,28.6%,23.9%,24.8% and 24.5% in males,and 13.8%,6.3%,7.9%,6.1%,6.2% and 6.8% in females for each year respectively.The prevalence of HUA in males aged 18 to 64 years old was significantly higher than that in the age-matched fe-males (all P＜0.05).However, the prevalence of HUA in males aged≥65 years old was similar to the age-matched females.There was no statistically significant difference of HUA prevalence between males and females aged ≥65 in 2013,2015,2016 and 2017 ( χ2＝1.792,0.017,1.440 and 0.205 respectively;all P＞0.05).The percentages of hyperlipidemia in both males and females of HUA group were higher than those of non-HUA group respectively (all P＜0.01).The percentage of hyperglycemia in males of non-HUA group was higher than that of HUA group,but the percentage of hyperglycemia in females of non-HUA group was lower than that of HUA group ( all P＜0.01).High levels of TC,TG and FBG were risk factors of HUA with increased OR values in increased concentrations of TC,TG and FBG,respectively.Conclusion During the recent 6 years, in healthy adults receiving physiced examination at PVMCH, the preva-lence of male HUA diagnosed was at overall high level,but the prevalence of female HUA was in decreasing and relatively stable trend. Hyperlipidemia and hyperglycemia should be the risk factors of HUA.

Comparative analysis of biochemical test results between arterial and venous blood / 中华检验医学杂志

Objective To investigate whether there are differences in the detection of biochemical items such as electrolytes , total protein and urea between arterial plasma and venous plasma .Methods Self paired design was used to compare and study the biochemical results of different samples .70 samples ( 36 samples from male patients and 34 from female patients ) that were performed with both arterial blood gas analysis and biochemical item test of venous blood in Clinical Laboratory of Peking Union Medical College Hospital during the period from June to September of 2017 were collected.18 biochemical items like electrolytes in arterial blood and venous blood were synchronously detected by automatic biochemical analyzer.Statistic analyses were carried out by SPSS 18.00.Whether the deviation was of clinic significance was determined by National Health Standards ( WS/T 403-2012 ) and the total error admitted by Royal Society of Pathology of Australia .Regression analysis of Passing-Bablok was performed by MedCalc software . The difference between the results of different samples was investigated by drawing Bland -Altman diagram.Results The results of Ca, Cl, K, Na, P, TP, ALB, ALT, AST, LDH, Glu, Cr, Urea, TG, CHO, UA, CHE, TBA in the samples of arterial blood plasma were 2.46(2.25-2.56) mmol/L,(105.68 ±7.29)mmol/L, 3.81(3.54-4.03) mmol/L, 140.45(137.08-144.20) mmol/L, 0.97(0.77-1.11) mmol/L,(60.39 ±9.40)g/L,(31.23 ±6.81)g/L, 17.4(11.95 -30.05)U/L, 20.85(14.9 -34.03) U/L, 210.1(163.15-342.60) U/L, 7.58(5.95-10.04) mmol/L, 76.35(51.05-110.7) μmol/L, 6.94(3.98-11.08) mmol/L, 1.15(0.84-1.89) mmol/L, 3.31(2.73-4.35) mmol/L, 271.55(187.78-423.30) μmol/L,(4.71 ±2.17)KU/L, 2.19(1.09 -4.19) μmol/L,respectively, and 2.24(2.05-2.35) mmol/L,(103.98 ±7.32)mmol/L, 3.84(3.58 -4.19) mmol/L, 139.30(136.08 -142.33) mmol/L, 0.99(0.78-1.14) mmol/L,(60.37 ±9.67) g/L,(32.62 ±6.89) g/L, 17.6(12.75-31.2) U/L, 20.6(15.28-36.6) U/L, 233.95(176.48-363.75) U/L, 7.55(5.62-9.52) mmol/L, 77.15 (56.08-111.98) μmol/L, 6.94(3.97 -10.53) mmol/L, 1.13(0.83 -1.93) mmol/L, 3.23(2.71-4.37) mmol/L, 273.4(187.30-401.55) μmol/L,(4.74 ±2.21) KU/L, 2.29(1.02 -4.23) μmol/L respectively in the samples of venous blood plasma .The difference of results of TP、Glu、Cr、TG、CHE、TBA between two types of samples were of no statistic significance ( the values of t or Z were 0.121,-0.054,-0.269,-0.480,-1.730 and -1.843 respectively, P>0.05), among these items the difference of Glu was of notable clinical significance (>1/2 TE percentage:50％).The difference of results of Ca , Cl, K, Na, P, ALB, ALT, AST, LDH, Urea, CHO, UA between two types of samples were of statistic significance (the values of t or Z were -7.115,6.794,-2.119,-4.996,-3.483,-8.839,-2.419,-2.742,-3.833,-5.010,-2.060 and -2.467 respectively, P<0.05), among these items the difference of Urea, CHO, UA, Na, P and ALT was of no notable clinical significance ( >total TE percentage: 0％, 2.86％, 0％, 2.9％, 4.3％, 1.43％ respectively), while the difference of Ca, Cl, K, ALB, AST and LDH was of clinical significance (>total TE percentage:90％, 10％, 14.3％, 32.9％, 10.00％, 32.9％respectively).Conclusions The differences in the detected data of some biochemical items between venous plasma and arterial plasma demonstrated clinical significance .When detecting those biochemical items , clinicians should pay attention to the selection of arterial blood sample .It should be considered to establish a reference interval for related biochemical items of arterial blood when necessary .

Quantification of human urine aldosterone by LC-MS/MS / 中华检验医学杂志

Objective To establish a method for quantification of aldosterone (ALD) in urine by LC-MS/MS.Methods This study was the establishment and validation of methodology for urine ALD using LC-MS/MS.The urine samples were hydrolyzed at 37 ℃ by hydrochloric acid and the deuterated isotope internal was then added , followed by protein precipitation and anion exchange solid phase extraction (SPE). After SPE, the eluates were detected in the negative electro-spray ionization mode and multiple reaction monitor mode.The linearity, lower limits of quantification , precision and recovery of LC-MS/MS were evaluated.Urine and serum ALD of 80 subjects were measured by LC-MS/MS to evaluate the correlation of ALD detected in serum and 24 h urine.70 urine samples were collected and measured with LC-MS/MS and CLIA method for ALD comparison.14 participants were recruited to study the distribution of urine ALD in apparent healthy population .Results The analytical time was 4.5 min.Linearity of ALD was good in the range of 2-1 000 pg/ml (R2＞0.990); the repeatability and CV of ALD were less than 4.0% and 5.0%respectively; the recovery of urine ALD ranged between 100.4%and 108.2%; the lower limits of detection was 1 pg/ml.The correlation between urine and serum ALD was 0.396.The method comparison resulted in linear equation Y＝0.998 8X+0.046 4(r＝0.991).The distribution of urine ALD in apparent healthy subjects were 0.74-17.09 μg/24 h.Conclusion A reliable and specific LC-MS/MS method for urine ALD was established.And condition of the acid hydrolyzation for urine ALD was optimized .The method is simple, rapid and it can be used for the diagnosis of primary aldosteronism.

Investigated the prevalence of hypouricemia in Peking Union Medical College Hospital / 中华检验医学杂志

Objective To investigate the prevalence and possible factors of hypouricemia in Peking Union Medical College Hospital.Methods A retrospective investigation.Serum uric acid, lipids, glucose and other chemistry tests were analyzed among 83176 outpatients(Male:30795,Female:52381), 15849 inpatients(Male:7402,Female:8447)and 24081 healthy subjects(Male:11859,Female:12222)in Peking Union Medical College Hospital from December 2015 to April 2016.Grouped by gender and age, the prevalence of hypouricemiawas analyzed in all subjects and the etiology and possible risk factors of hypouricemia were explored among all patients.Results The serum uric acid of outpatients,inpatients and healthy subjects were 286(235-348)μmol/L, 282(226-348)μmol/L and 298(244-358)μmol/L, respectively.And the prevalence were 0.6%(499/83176),2.5%(390/15849)and 0.2%(39/24081), respectively.The prevalence of hypouricemia ofwomen was significantly higher than that ofmen(outpatients:0.7%vs 0.4%,P<0.001;inpatients:2.8%vs 2.1%,P=0.004;healthy subjects:0.30%vs 0.04%, P<0.001).After analyzing 507 hypouricemia patients, the top three clinical diagnoses that related with hypouricemia were kidney diseases, tumor and rheumatic diseases.Compared with the control group, the prevalence of hypouricemia in hypertriglyceridemia group and group with eGFR higher than 90 ml/(min· 1.73 m2)were lower(OR:0.33, 95% CI:0.21-0.50; OR:0.16, 95% CI:0.09-0.29), and the prevalence of hypouricemia in hyperglycemia group was higher(OR:1.62, 95% CI:1.12-2.35). Conclusion The prevalence of hypouricemia of Chinese women was higher than that of men and may be related with TG,Glu and eGFR.

Chemical constituents from Cucurbita moschata leaves / 中成药

AIM To investigate the chemical constituents from the leaves of Cucurbita moschata (Duch.ex Lam.) Duch.ex Poiret.METHODS The ethyl acetate and n-butanol fractions of 70％ ethanol extract from C.moschata leaves were isolated and purified by silica,Sephadex LH-20,ODS and preparative TLC,then the structures of obtained compounds were identified by physicochemical properties and spectral data.RESULTS Thirteen compounds were isolated and identified as β-amyrin (1),phytol (2),α-linolenic acid (3),α-methyl linolenate (4),palmitic acid (5),ethyl linoleate (6),ethyl palmitate (7),daucosterol (8),β-sitosterol (9),(6S,9R)-roseoside (10),soya-cerebroside Ⅰ (11),dibutyl phthalate (12),4,4'-diphenylmethane-bis (methyl) carbamates (13).CONCLUSION All the compounds are isolated from this plant for the first time.

Preparation of cholesterol and glycerol reference materials in cyclodextrin aqueous solution / 中华检验医学杂志

Objective Preparation of aqueous reference materials for cholesterol and glycerol.Methods Study on reference materials.The certified reference materials GBW09203b and GBW09149 were weighed accurately and dissolved into 20% of methyl cyclodextrin aqueous solution to prepare six kinds of candidate reference materials of cholesterol and glycerol according to the concentration.The materials were tested for homogeneity and stability using routine methods.The reference methods of isotope dilution liquid chromatography tandem mass spectrometry (ID-LC/MS/MS) were used to determine the concentration of cholesterol and glycerol to evaluate the accuracy of the certified values.Meanwhile, the blank verification test was carried out.The expanded uncertainty was the combination of standard uncertainty of measurement, unhomogeneity and instability.Results It showed that the six candidate reference materials were homogeneous and stable for at least 1 year at-70 ℃ and-20 ℃.The certified values (reference value ± expanded uncertainty,mmol/L) were as follows,for cholesterol:0.65±0.01,1.31 ±0.01,2.57±0.02,5.21±0.06,7.71±0.08,10.24±0.06;for glycerol:0.29±0.01,0.58±0.01,1.22±0.02,2.24±0.02,3.46±0.04,4.52 ±0.04.The results of reference methods were consistent with the certified values.Blank validation tests showed that the concentration of the analytes would not be affected by the reagent and the blank matrix.Conclusions Certified reference materials for cholesterol and glycerol in aqueous solution have been prepared successfully.These materials are homogeneous and stable, and the certified values are reliable.Therefore the materials have been approved to be the Certificate Reference Materials of GBW 09823, GBW 09824, GBW 09825, GBW09826, GBW09827 and GBW 09828.

Survey of vitamin D status in apparently healthy younger and elder adults / 中华检验医学杂志

Objective To analyze the vitamin D status among apparently healthy younger and elder adults in Beijing based on liquid chromatography tandem mass spectrometry.Methods This is an observational study.Participants included 287 apparently healthy young adults(143 males and 144 females) with an average of (32.2 ± 6.9) years old (19-44 years).At the same time 198 middle-and elder-aged adults were recruited [90 males,108 females,(55.6 ± 7.6) years],and fasting blood samples were collected and serum were isolated.They measured 25-hydroxyvitamin D (25OHD:25OHD2 and 25OHD3)using liquid chromatography tandem mass spectrometry method.Vitamin D with deficiency,insufficiency,sufficiency and intoxication was categorized as 25OHD ＜ 20 ng/ml,20-30 ng/ml,30-150 ng/ml,and ≥ 150 ng/ml,respectively.ALT,Ca,P,Cr,Glu,TG,TC and iPTH wereanalyzed using automatic analyzers.Statistical analysis was performed using SPSS17.0.Results The median 25OHD level in the total studied younger adults was 16.0 [2.5％-97.5％:(6.1-29.0) ng/ml] which didn't show significant difference with that of middle-and elder-aged adults.Younger males had significant higher level of 25OHD than females [17.9 (8.3-32.3) ng/ml vs.14.4 (5.4-26.4) ng/ml,Z =-4.238,P ＜ 0.01].Of the total younger subjects,the rate of vitamin D with deficiency (＜ 20 ng/ml),insufficiency (20-30 ng/ml)and sufficiency (≥30 ng/ml) was 72.8％,25.1％,2.1％,respectively,while that of middle-and elderaged adults was 76.3％,21.2％,2.5％ respectively,and that of younger males was 65.0％,30.8％,4.2％,respectively while that of younger females was 80.6％,19.4％,0％,respectively.Younger females had significantly higher rate of 25OHD deficiency (x2 =31.766,P ＜ 0.01).With adjusting sex,age and BMI,serum iPTH (r =-0.264,P ＜ 0.01) was significantly negatively correlated with 25OHD while Cr (r =0.221,P ＜ 0.01) showed significantly positively correlation with 25OHD.Conclusion Vitamin D deficiency is prevalent in both younger and elder adults in Beijing,especially in younger females.

Performance verification of six enzymatic glycated albumin reagents / 中华检验医学杂志

Objective To validate the performance of six enzymatic glycated albumin reagents and evaluate their clinical application.Methods The performance of six enzymatic glycated albumin reagents(labled as A,B,C,D,E,F) from Beijing Jiuqiang Co, Beijing Lideman Co,Ningbomeikang Co, Beijing Haomai Co, Sichuan Maike Co and Asahi Kasei Co were assessed on Olympus AU5800 automatic biochemistry analyzer.According to the standard of CLSI,the precision,interference and linear correlation of these reagents were assessed.To assess the accuracy of GA% ,we used GA standard material whose value had been assigned using ID-LC/MS method provided by ReCCS.To do the method comparison and determine the consistency of assay, 50 fresh serum samples of T2DM outpatient and 80 fresh serum samples of apparently healthy people in Jan 2016 were tested using six kits.According to the EP28-A3C protocol, the reference range for GA%was validated in 122 apparently healthy individuals undertaking medical examination from January to February 2016 in PUMC.Results The precision,and the ability of anti-interference of the six reagents were good.The accuracy percentage deviation of six reagents was-19.3%-9.2%.The correlation coefficient of domestic reagents A to E and imported reagents F in the determination of GA% was 0.966-0.999, the average absolute bias was 7.0%-10.4%.The coincidence rate of A-E and F in determining abnormal GA% was between 88.5% and 96.9%.The coincidence rate was increased after switching to the reference range for preliminary clinical evaluation.Conclusion Six GA enzymatic kits used in automatic biochemical analyzer have high precision and strong anti-interference ability.Accuracy still needs to be improved.

Quantification of human urine and serum iodine by inductively coupled plasma mass spectrometry / 中华检验医学杂志

Objective This paper aims at establishing a inductively coupled plasma mass spectrometry ( ICP-MS) method for quantification and evaluation of iodine in human urine and serum in routine clinical laboratory .Methods This study was methodology validation research on iodine evaluation using ICP-MS.Ammonia, isopropanol and ultrapure water were mixed at certain ratio to dilute samples in the ratio of 1:10, and then the diluted samples were analyzed by ICP -MS.Re was used as the internal standard.And linearity, lower limit of detection, recovery, precision, accuracy, carryover and stability was evaluated thoroughly .Results of iodine of pregnant women who required iodine tests were retrospectively analyzed to evaluate the status of iodine .Results The method only needs 30s for analysis of one sample .It was sensitive with a lower limit detection of 0.87μg/L, the correlation coefficient was higher than 0.999 9 in ten measurements.The recovery in both serum and urine was approximately 100% (95.3% -109.9%). Based on the NIST standard reference material 3668 comparison, the bias was less than 4%( -0.9% -3.9%).The inter-coefficient variation (CV) for serum iodine and urine iodine was 1.2%-3.0%, 2. 0%-2.9%, respectively;and total CV for serum iodine and urine iodine were 3.0%-3.8%, 4.1%-4.9%, respectively.The mean carryover of this method was 0.03% and iodine was stable for at least one month at -20℃ and 4℃.The urine and serum iodine for pregnant women was (154.8 ±89.7) μg/L (mean ±SD),(75.8 ±21.4) μg/L, respectively.The correlation between urine and serum iodine was 0.21. Conclusion Establishe a rapid and simple ICP -MS method for urine and serum iodine measurement with high accurate and precise in routine clinical laboratory .

Preparation of reference materials of total thyroxine / 中华检验医学杂志

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.

Negative interference by calcium dobesilate in uricase-peroxidase coupled assays of serum uric acid / 中华检验医学杂志

Objective To assess the interference by calcium dobesilatein 7 peroxidase-baseduric acid assays and to determine its clinical significance.Methods In the in vitro experiments, uric acid in pooled serum with final concentrations of calcium dobesilate additions (0, 2, 4, 8, 16, 32, and 64μg/ml) were measured by 7 peroxidase-based assays.Percent Bias (%) was calculated relative to the drug-free specimen.In the in vivo experiments, changes in serum uric acid and calcium dobesilate concentrations were observed before and after calcium dobesilate administration ( baseline, 0 h, 1 h, 2 h, 3 h, 4 h, 6 h ) involunteers.The interference in different assays was assessed compared with LC-IDMS/MS method. Calcium dobesilate levels in 40 specimens from those taking calcium dobesilate were measured by HPLC method.Of the 40 specimens, 10 were selected to analyse the levels of uric acid by both peroxidase and UV measurement method to assess the impact in clinical status.Results In the in vitro study, concentrations of uric acid measured by 7 peroxidase-based assays were reduced by -6.3%to -21.2%compared with drug-free serum, when theconcentration of calcium dobesilate was16μg/ml.In the in vivo study, comparedto UA levels at 0 h, the biasesof serum uric acid determined by peroxidase method after calcium dobesilate administration(1 h, 2 h, 3 h, 4 h, 6 h) were of -3.33%, -6.79%, -7.49%, -6.07%, -4.09%, respectively.The observed uric acid concentrations for 8 participants measured by enzymatic assays were inhibited by -3.75% to -6.89% at 0 hour and by -16.9% to-22.22% at 2 hours relative to the concentrations measured by the LC-IDMS/MS method. Conclusions Calcium dobesilate produced a clinically significant negative interference with uric acid in all peroxidase-based uric acid assays,which may result in false evaluation of uric acid level in clinical status.Significant differences in the degree of interference were observed among the assays.