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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.
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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.
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Humans , Bias , Diagnosis , Immunoassay , Mass Spectrometry , Methods , Thyroid Gland , Thyrotropin , ThyroxineABSTRACT
Objective To study the relationship among rs505802 in SLC22A12,rs6855911,rs737267,rs12498742, rs7442295, rs734553, rs16890979 in SLC2A9 genetic polymorphisms and hypouricemia in Ningxia.Methods 6 056 subjects were collected by multistage,stratified random cluster sampling method in October and November in 2011 in Ningxia Hui autonomous region, 98 subjects with hypouricemia were selected.According to gender and age,84 controls were selected.Physical examination and laboratory biochemical index test were conducted for the study population.T test was used to compare general clinical data and biochemical indexs between two groups. SNPs were detected by Sequenom Mass ARRAY technology.By x2test,we compared the frequencies of the geno-type and allele in each group.Samples representativeness was confirmed through the Hardy-Weinberg inspection. Results The levels of TC, LDLC, and Cr in the patients were lower than those in the control group(P<0.05). There were significant differences in the distribution of A,G allele frequencies of SLC2A9 gene rs7442295 between two groups.The risk of hypouricemia in patients with A/A genotype was lower than that of A/G genotype(Pc<0.05),indicating that A>G mutation was associated with hypouricemia.Conclusions Polymorphisms of SLC2A9 gene rs7442295 are significantly correlated with hyporuricemia in Ningxia.
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Objective To analyze and deal with false positive results caused by heterophile antibody interference immunoas say.Methods A 65 year old male patient's plasma samples were processed by dilution method,heterophile antibody blockers and tested using different detection systems (Beckman,Siemens and Abbott),respectively.The results obtained by multi plied dilution and different detection systems as well as pre and post-processed by heterophilic antibody blockers were compared and analyzed.Results The Beckman system was used to detect plasma cTnⅠ in patients before dilution and multiplied diluted at 2,4 and 8 times,with the results of 4.60,4.03,3.45 and 2.62 ng/ml,respectively.The cTnⅠ results of the patient's plasma determined by Beckman,Siemens and Abbott system were 4.60,0.023 and 0.022 ng/ml,respectively.The plasma cTnⅠ results of before and after heterophilic antibody blockers processing determined by Beckman system were 4.60 and 0.106 ng/ml respectively.Conclusion This cTnⅠ assay of the patient's plasma was interfered by heterophile antibodies,and altering the detection system or utilizing heterophile antibody blockers can solve such interference effectively.
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Objective To evaluate the perioperative changes of h-FABP,IMA,IL-2R,IL-6,IL-8,TNF-α and MPO in patients with PCI.Methods The serial serum samples from 34 patients were collected from November of 2011 to February of 2012 in coronary care unit of Peking Union Hospital on separately 2,4,8 and 24 hours after PCI,then IL2R,IL6,IL8,TNF-α,h-FABP,IMA and MPO were measured.Results MPO,h-FABP and CKMB increased dramatically at 2 hours after PCI(Z value were separately-3.621,-5.123 and-2.789 compared with the level at 2 h and 24 h,all P＜ 0.05),and h-FABP within 24 hours fell into the normal range.MPO dropped quickly after 4 hours of surgery and CKMB peaked at 4 hours,then decreased.The concentration of CK and cTnⅠ rose up at 4h (Z value were separately-2.803 and-2.31 compared with the level at 2h and 24 h,all P＜0.05) and declined with a climax at 8h after PCI.The correlation coefficient of CKMB and CK with cTnⅠ were higher than 0.6.Conclusion This study provided an overview of the change of multi-biomarkers following PCI,which gave a valuable information for clinical treatment.
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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.
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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.
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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.
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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 .
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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.
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Objective To assess the consistency of four standardized cystatin C particle-enhanced turbidimetric assay (PETIA) and one particle-enhanced nephelometric immunoassay (PENIA) measurement systems Methods Performance verification test was conducted according to CLSI EP 15-A2 and EP9-A2. Fourty serum samples in comparative test were obtained from the remaining serum samples of outpatients in Peking Union Medical College Hospital in March 2013.Fourty serum samples were tested on Olympus AU5400 automatic biochemical analyzer ( four PETIA Cys C reagents:Shanghai Jingyuan Co ., Ltd, Beijing Leadman Biochemistry Co ., Ltd, Beijing Strong Biotechnologies , Maker Biotechnology in Sichuan , and labelled as A, B, C, D respectively) and PENIA N Latex Cys C measurement system on Siemens BNⅡ(labelled as E).Correlation analysis were performed among four PETIA methods one PENIA method Differences of each detection system were compared in the medical decision level 1,2,3,4 mg/L.The reference material ERM-DA471/IFCC was measured by five systems and bias ( percentage bias ) was calculate for each system.Results Results of systems A, B, C, D, E were 1.29(0.89-2.43), 1.30 (0.96-2.59), 1.22(0.90-2.44), 1.27(0.96-2.47), 1.14(0.82-2.05)mg/L.Chart shows bias among these five systems was small when Cys C concentration was less than 4mg/L.PETIA method A, B, C, D correlated with their mean value well , with the average deviation from their mean value ( percent deviation) at -0.017 -0.031 mg/L ( -3.1%-2.1%), and all were less than allowed bias from the biological variation (3.4%).The deviation of PETIA method A, B, C, D with their mean value in medical decision level at -0.176 -0.178 mg/L.Systems A, B, C, D correlated well with the result of PENIA method system E , and the mean deviation ( percent deviation ) was at 0.278 -0.326 mg/L ( 12.6%-18.5%) , and the deviation ( percent deviation ) in the medical decision level 0.055 -1.079 mg/L (5.51%-26.98%).Bias of PETIA method A, B, C, D Cys C system measuringERM -DA471/IFCC ranged from 0.22 to 0.39 mg/L ( 3.9%-7.0%) , which exceeded the allowable range of the reference material target value, and were larger than the allowable bias from biological variation (3.4%).Bias ( percent ) of PENIA method system E was -0.1 mg/L ( -1.7%) , within the allowable range of ERM-DA471/IFCC target value .Conclusions The consistency of four assesed PETIA Cys C reagents was relatively ideal, and improved markably after being traced to ERM-DA471/IFCC.Besides, the results of PETIA were higher than those of PENIA .Bias among these five systems was small when Cys C concentration was less than 4 mg/L, and the bias became larger in higher Cys C concentration.