Objective To explore the verification methods for the performance of quantitative detection kit of anti-dsDNA antibodiy with enzyme-linked immunosorbent assay (ELISA).Methods The precision was verified according to the EP15-A2 document approved by the American Clinical and Laboratory Standards Institute(CLSI).The accuracy was verified by detecting the samples of previous external quality evaluation(EQA),compared with the comparative kits and recovery test.The lower limit of detection(LLD) was calculated by the results of blank samples.The cut-off value was verified according to the C28-A3C document approved by CLSI and CNAS-CL39:Guidance on the Application of Accreditation Criteria for the Medical Laboratory Quality and Competence in the Field of Clinical Qualitative Immunology respectively.The improved Doumas method was used to verify the range of linearity.Results The measured intra-assay and inter-assay coefficients of variation were lower than those announced by the manufacturer or the calculated values according to the EP15-A2 document.The coincidence rates for negative and positive EQA samples between detected and expected values were 98.4％ (63/64) and 100％ (20/20) respectively.The total coincidence rate was 98.8％ (83/84).The coincidence rate for negative and positive samples between the results from candidate and comparative kits were 91.2％ (52/57) and 87.0％ (40/46) respectively.The total coincidence rate was 89.3％ (92/103) and the Kappa value was 0.783 (P =0.062),which implied excellent consistency between the two kits.The mean recovery rate was 99.65％.The measured LLD was 0.5 IU/mL which was lower than 1 IU/mL as claimed by the manufacturer.The measured cut-off value according to the CNAS-CL39 document was 18.51 IU/mL,which was close to 20 IU/mL announced by the manufacturer.Based on the C28-A3C method,the cut-off value could be approved.The linear regression equation was Y =0.978 8X-3.125 4,r2 =0.996 1.There was no statistical difference between the intercept (-3.125 4) and 0 (t =-0.772,P =0.483).The range of linearity was from 1.6 to 212.5 IU/mL,which was consistent with the values declared by the manufacturer.All the verifications of the five performances above-mentioned could be passed.Conclusion The precision,accuracy,LLD,cut-off value and range of linearity of the candidate quantitative ELISA kit for anti-dsDNA antibody were consistent with the statement of the manufacturer,which indicated the performance of the kits may meet the requirements of clinic diagnosis and treatment.A series of methods used in this study provided a simple protocol for verifying the performance of quantitative ELISA kits.

Objective To investigate the accumulative 3-year morbidity of diabetes in the residents aged 40 years and above in a community of Guiyang and the risk factors. Methods A total of 10140 permanent residents aged over 40 years in a community of Guiyang were selected from May 2011 to October 2011 using randomized sampling. This population was followed up again in 2014. Questionnaires, physical examination, blood lipids and oral glucose tolerance test were performed among the subjects of study for two surveys with the same criteria. Finally, 5958 subjects with complete data and without baseline diabetes at the two time points were enrolled in this study for analysis. Results The 3-year accumulative morbidity of diabetes in this population was 6. 13％ (6. 59％ in males, 5. 65％ in females). The main factors influencing the incidence of diabetes mellitus were age (OR = 1. 589, 95％ CI 1. 395-1. 809, P<0. 01), body mass index ( OR = 2. 012, 95％ CI 1. 632-2. 479, P<0. 01), pulse rate ( OR =1. 019, 95％ CI 1. 012-1. 025, P<0. 01), family history (OR = 1. 700, 95％ CI 1. 299-2. 225, P<0. 05), fasting plasma glucose at baseline(OR = 3. 132, 95％ CI 2. 478-3. 958, P<0. 01), 2 h plasma glucose at baseline( OR =1. 698,95％ CI 1. 574-1. 832, P < 0. 01), total cholesterol ( OR = 1. 350, 95％ CI 1. 060-1. 719, P < 0. 05), triglyceride(OR=2. 196, 95％ CI 1. 758-2. 743, P<0. 01),high density lipoprotein-cholesterol(OR = 0. 540, 95％CI 0. 375-0. 776, P < 0. 01), and low density lipoprotein-cholesterol ( OR = 1. 614, 95％ CI 1. 094-2. 382, P<0. 05). Conclusion 3-year morbidity of diabetes in Guiyang was 6. 13％ . The incidence of diabetes is notably correlated with aging, faster pulse frequency, overweight and obesity, higher baseline blood glucose, and dyslipidemia.

Objective:To explore the predictive value of brachial-ankle pulse wave velocity (baPWV)>1 400 cm/s in fragility fracture in middle-aged and elderly population.Methods:From May to October 2011, questionnaire survey was conducted on a total of 3 265 males over 50 years old and postmenopausal females in Yunyan District, Guiyang City, and physical examination was carried out to measure their metabolic related indicators such as blood lipids, QUS calcaneus bone densities, and brachial-ankle pulse wave velocities. According to their baPWV, the enrolled subjects were divided into a normal baPWV group and an elevated baPWV group. Follow-up was performed for 38 months, and the incidence of fractures was tracked. Finally, 2 637 subjects with complete baseline and follow-up data were enrolled in this research for analysis.Results:The 3-year total incidence of fragility fracture was 5.08%. In particular, the rate of fragility fractures among males in the normal baPWV group was 1.6%, and that in the elevated baPWV group was 2.0%. There was no statistically significant difference between the two groups ( P>0.05). The rate of fragility fracture events among postmenopausal females in the normal baPWV group was 4.4%, and that in the elevated baPWV group was 7.1%. There was statistically significant difference between the two groups ( P<0.05). Further multivariate COX regression (or proportional hazards regression) analysis showed that the bone density T value ( HR 0.839, 95% CI 0.741-0.952, P=0.006) and baPWV ( HR 1.700, 95% CI 1.046-2.763, P=0.042) were related with risk of fragility fractures in postmenopausal women. Conclusion:A baPWV greater than 1 400 cm/s could be independently associated with the risk of fragility fractures in postmenopausal females and might be an independent risk factor for predicting fragility fractures. However, such differences were not as evident in middle-aged and elderly male patients.