RESUMO
Objective To evaluate the trueness of 13 routine measurements for serum uric acid and the role of reference method in improving harmonization and trueness among routine measurement systems. Methods The research is related to the reagent evaluation.Usingisotope dilution liquid chromatography tandem mass spectrometry ( ID-LC/MS/MS) method as the comparison method, Wako, Sekisui, DiaSys, Maker,Dirui,Leadman,BSBE,Biosina,Mindray,MedicalSystem,LongMarch,and Kehua 13 kinds of uric acid kits were chosen as the evaluation methods with Hitachi 7170A as the analyzer.serum uric acid in 40 fresh frozen serawere collected from clinical laboratory of Beijing hospital in 2014,coveringboth physiological and pathological status ( 80 -940 μmol/L ) .19 kinds of prepared materials and the 40 fronzen sera were measuredby comparison method and evaluation methods and linear regression analysis was made for the results.The performance of evaluation methods was revealed and recalibration was performed on every evaluation methodby the linear regression equation.The variation of percent bias(%) of the uric acid values in 19 preparation materials was compared.Results All test methods demonstrated good precision ( CV0.998, P<0.01) with the comparison method when measuring uric acid values in 40 fresh frozen sera The meanpercent bias was 0.17% ( -3.06% -7.31%).After recalibration, 4 of 19 samples with no matrix effect values percent bias reduced and met the demands of quality ( <4.8%) induced from biological variation.Conclusion All test methods demonstrated good trueness and their calibration traceability was verified.Recalibration using reference method or standard reference materials contributes to harmonization among methods.
RESUMO
BACKGROUND:Bilateral-sagitta-split-ramus-osteotomy (BSSRO) has become a conventional method to correct facial deformities, and the finite element method is a significant way to study biomechanics of the mandible and temporomandibular joint (TMJ) after BSSRO. OBJECTIVE: To establish a precise and high simulation model of mandible containing TMJ after BSSRO with internal fixation, which is the base to study the biomechanics of the mandible and TMJ after BSSRO. METHODS: Spiral CT scan was used to get the data of DICOM that were input into MIMICS to establish the three-dimensional model of the mandible. The three-dimensional model was wrapped into a single closed shel for mesh generation and conversion in ANSYS. Then, the model was input into the ANSYS software for temporomandibular joint reconstruction and simulation of BSSRO and internal fixation. RESULTS AND CONCLUSION: The three-dimensional finite element model of mandible containing TMJ after BSSRO was established using MIMICS and ANSYS. This model had biological similarity and geometric similarity in comparison with the human tissues. The model could undergo various internal fixations through antedisplacement, retroposition and rotational movement of the distal end. Based on different experimental purposes, the established model can apply a load to al parts to study changes in stress and displacement of different tissues after BSSRO and internal fixation, and it also can be used to study the effect of different fixation materials on the rear stability after internal fixation.