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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.
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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.
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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.
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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.
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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.
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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.
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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.
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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.
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Objective To evaluate the analytical performance of four lipoprotein associated phospholipase A2(Lp-PLA2)activity reagents on Beckman AU5800 automatic biochemical analyzer. Methods The remaining serum samples of 214 patients and 140 apparently healthy individuals were collected from March to July 2017 in Peking Union Medical College Hospital.These samples were used for method comparison and reference interval evaluation.According to the guidelines of EP15-A,EP6-A,EP-17 and EP7-P from Clinical and Laboratory Standards Institute(CLSI)standards,the precision, linearity, sensitivity and common interferences(e.g free bilirubin, conjunct bilirubin, hemoglobin and chyle)were assessed.According to EP9-A2,method comparisons of differents regents(Evermed,DiaSys,Hengxiao and Zhongyuan were labeled as A,B,C and D,respectively)were conducted and the differences were estimated at medical decision levels(328U/L,391U/L and 485U/L).Results The precision of four reagents were acceptable.The repeatability(CV%)of A to D were 0.5%-1.7%, 0.7%-3.0%, 0.9%-2.0% and 0.5%-3.3%,respectively.The reproducibility(CV%)were 0.7%-2.9%, 1.4%-3.2%, 1.3%-1.9%and 0.8%-4.1%,respectively.Both of those achievedlaboratory defined quality objective(<5%).The linearity of A to D were 44 -1 992 U/L,39 -1 798 U/L,13 -540 U/L and 75-1 717U/L,respectively.The regression coefficient R2 was between 0.997 and 1.000, and the correlation coefficient(r)was between 0.998 and 1.000.The interference of chyle were acceptable among these four reagents andmet the manufacturer′s requirementsor clinical needs.In a low level of Lp-PLA2,bilirubin had an obvious interferenceonreagent C;B and C were negatively affected when the hemoglobin was 4.5 g/L; and D was positively affected when the hemoglobin was 2.45 g/L.The regression coefficients R2 of A,C,D compared with B were between 0.978 and 0.995,and the correlation coefficients(r)were between 0.989 and 0.998. The expected differences at medical decision levels ranged from -240 U/L to 113 U/L.For A to D,the Lp-PLA2 activity results of 131(93.6%), 140(100%), 82(58.6%), and 128(91.4%)cases were analysed within the manufacturer′s claimed reference intervals.Conclusion The precision and linearity of the four Lp-PLA2 activity detection reagents used in automatic biochemical analyzer are good, but the anti-interference ability needs to be improved.