| Background and PurposeSerum Total Cholesterol (TC) is an important routine laboratory measurement items, IT has great significance in the diagnosis and prevention of cardiovascular diseases in hyperlipidemia. Determination of serum total cholesterol is measured lipoprotein form of free cholesterol and cholesterol ester in blood. Most routine laboratory determination of total cholesterol was measured enzymatically, the method is simple, fast, convenient and suitable for mass measured on a biochemical analyzer. However, the equipment reagents,-calibrators diversified in routine laboratory, in order to make the results of routine laboratory determination of accurate and consistent, we need to use a reference measurement system to standardize its measurement. Backtracking the Ministry of Health EQA results and CAP EQA results of Peking Union Medical College Hospital clinical laboratory from the year 2008 to 2010, because of differences EQA different grouping matrix effects and interpretation of the results are different too. And verify the accuracy of the results and the measurement results were purchased from Beijing Institute of Geriatrics, the standard lipid material is basically the same. Routine laboratory results traceability requirements and reference measurement system verification, so as to ensure the consistency of the results and the accuracy of the results between the various routine laboratoryIn this study reproduced the ultrahigh-pressure liquid high pressure liquid measuring cholesterol candidate reference method, the initial attempt to use ultra high pressure liquid reproducible reference method to assign a single source of fresh frozen serum and try it for 14 calibration of conventional systems. Discussion of this multi-system model to improve the consistency of the possibility of blood lipids measured.MethodUsing cholesterol ethanol solution as the standard solution, using stigmasterol as an internal standard, with a reproduction of the ultra high pressure liquid high pressure liquid measuring cholesterol candidate reference method. Specimens from the same source of support serum, the present study reproduced reference method assignment and verify their homogeneity and stability. We conducted two five systems and 14 systems comparison, than conventional calibration standard material and calibration modes for testing different concentrations of 54 parts of fresh pooled serum. Correlation analysis and reference system deviation of the results of analysis performed, and analyzes the deviations in the medical decision level and variation for each sample under the two calibration methods.ResultMeasured by high pressure liquid reference method of reproducing the total cholesterol, the results of bias and NIST SRM 0.75%; intra-assay precision were less than 1.0%, inter-assay precision were less than 3.0%. Assignment of fresh frozen serum by conventional enzymatic detection of CV were less than 1.0%; 90 days of good stability, the assignment result is 4.56mmol/L, reference test method imprecision was 0.65%.In the two alignments imprecision of each system can meet the requirements, in the first attained on the determination of TC, in addition to C system level CV exceeds the NCEP criteria (<3.0%), other systems are precision acceptable; TG each system to meet the NCEP criteria (<5.0%); the second attained on precision standards are met NECP.In the first comparison the various systems of TC and TG measured values and the corresponding calibration methods Determination of group means to do correlation analysis, r2 were between 0.95 to 1.00, there was no significant difference; the second comparison the TC Determination of C routine calibration and system calibration and reference standard material method has significant difference; E system has significant difference of the reference method in routine calibration time, there was no significant difference after calibration standard material. Determination of TG use A (P) as the reference system, two calibration mode under C system were significant differences; in the H system routine calibration significant difference, no significant difference was after the standard calibration.In the first comparison, in the determination of TC medical level of absolute deviation than NCEP under conventional calibration standard (< 3.0%) is 4, the calibration of medical level of absolute deviation over NCEP standard (< 3.0%) with zero; TG measurement in the medical level of absolute deviation than NCEP under conventional calibration standard (< 7.5%) 2, the calibration of medical level of absolute deviation over NCEP standard (< 7.5%) one. TC in the determination of the second alignment medical level of absolute deviation than NCEP under conventional calibration standard (< 3.0%) has 15, standard calibration under the medical level of absolute deviation over NCEP standard (< 3.0%) has four; TG measurement in the medical level of absolute deviation than NCEP under conventional calibration standard (< 7.5%) of 16, the calibration of medical level of absolute deviation over NCEP standard (< 7.5%) with 12.Variation of both calibration methods comparison between the various systems, first comparison routine testing results in the TC 2.19 ~ 23.43% variation, mutation detection results of the calibration standard is 1.35 to 5.05%; variation TG routine test results 3.76 ~ 23.65%, the variation of the standard substance calibration test results from 0.66 to 18.43 percent. The second comparison Variation, TC routine testing results was 4.79 ~13.83%, the variation of the standard substance calibration test results 2.94-7.60%; variation TG routine test results is 5.44~ 24.67%, standard substance calibration test results variation of 2.92 ~ 14.00%. Traceability chain at relatively high serum assignment for unity after calibration, significantly reduce the difference between the results of each system.ConclusionThe high pressure liquid research reproducible measurement TC reference method accuracy and precision meet the requirements, the use of their assignment fresh frozen serum, and then applied to the different detection systems unified calibration, can effectively improve the consistency of the results. |
PDF Full Text Request