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Determining whether patients have volume-responsiveness is one of the frequently asked questions in the intensive care unit, especially in shock patients. Evaluating the volume status and volume responsiveness can help clinical medical staff accurately grasp the patient's cardiac preload, guide reasonable volume management, and help improve patient prognosis. Therefore, many non-invasive and invasive methods have been proposed to evaluate volume responsiveness. Inferior vena cava ultrasound has been widely used to guide the fluid management of critically ill patients due to its simplicity, non-invasiveness, and good repeatability. This article reviews the clinical applications of inferior vena cava ultrasound in fluid management of critically ill patients, so as to provide a reference for circulatory management of critically ill patients.
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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 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 explore the positive rate of intrinsic factor antibody (IFAb) and level of vitamin B12 (VitB12) in normal physical examination population and the possible relation between IFAb, VitB12 and sex, age, number of RBC, HGB and MCV.@*Methods@#A total of 1 427 people who came to Peking Union Medical Colleague Hospital (PUMCH) for physical examination were enrolled. There were 758 males with average age of (52.5±14.5) years-old and 669 females with average age of (50.3±14.3) year-old. Beckman DxI800 automatic biochemical-immune analyzer and corollary reagents were used to analyze the level of serum IFAb and VitB12. The results in different sex, age were documented and their correlation with the value of whole blood cell count was tested later on.@*Results@#Among the 1 427 normal subjects, 66 (4.63%) were positive for IFAb. The positive rate for IFAb in the population≥40 years-old was higher than those<40 years-old (5.66% vs 1.48%, χ2=7.46, P=0.006). The deficiency rate of VitB12 in the population<40 years-old, 40-59 years-old and ≥60 years-old was 2.22%, 2.51% and 5.50%, respectively (χ2=8.55, P=0.014). There were no difference between people with different sex in the positive rate of IFAb (5.15% for males and 4.04% for females, χ2=0.99, P=0.320) or in the deficiency rate of VitB12 (3.83% for males and 2.69% for females, χ2=1.44, P=0.230). The results of multiple linear regression showed that HGB level of IFAb positive subjects was 3.05 g/L lower on average than those of IFAb negative, but IFAb had no effect on both RBC and MCV. There was no correlation between VitB12 deficiency and HGB, RBC and MCV.@*Conclusion@#The positive rate of IFAb and deficiency rate of VitB12 increase as age increases. But the presence of VitB12 deficiency is later than the positive findings of IFAb. IFAb showed some effects on the level of HGB, which may compensate the limitations of VitB12 detection to some extent. It is necessary to check the IFAb and level of VitB12 in people with middle or old ages.
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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.
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Objective To clone the full length staphylococcal protein A(SPA) gene from Staphylococcus aureus (ATCC6538), and subsequently study the gene structure and antibody binding ability.Methods The full length and the functional region of the SPA gene were cloned into pHisSUMO vector respectively, and expressed in E. coli. The full length and the functional fragment of the SPA protein were detected for antibody binding ability and stability. The functional fragment of the SPA protein fused with SUMO was coupled to the CNBr-activated agarose for antibody purification from rabbit serum. Results A variant of the full length SPA gene was cloned, which has been submitted to GenBank (the accession number is EU695225). Two fusion proteins had the same antibody binding ability as the untagged SPA protein. However, the formers was more stable than the latter at the tested conditions. SUMO-SPA conjugated-agarose kept high efficiency for antibody binding. Conclusion To our knowledge, the full length SPA gene of S.aureus(ATCC6538) is a novel variant. The SUMO tag can improve the stability of the functional region of the SPA protein without damaging the antibody binding ability. This fusion protein has been used for antibody purification successfully.
