| Part 1 Genotype distribution of Thalassaemia patients in GuangzhouObjectives To detect the thalassemia gene in people in Guangzhou area,to understand the distribution of thalassemia gene in this area,and to provide clinicians with genetic counseling and prenatal diagnosis data.Methods To collect the cases of thalassemia gene laboratory examination conducted in the Department of Laboratory Medicine of Guangdong Hospital of Traditional Chinese Medicine from 2017 to 2019.Gap-PCR was used to detect-impoverish,and reverse dot blot(RDB-PCR)was used to detect-impoverish and non-deletion-impoverish.Whole blood analysis(CBC),including RBC count(RBC),RBC distribution width(RDW),hemoglobin(Hb),RBC mean volume(MCV),RBC mean hemoglobin(MCH),and RBC mean hemoglobin concentration(MCHC),were performed on peripheral blood by automatic hematology analyzer.Using the VARIANT Ⅱtype automatic capillary electrophoresis apparatus of hemoglobin component(Hb A2,Hb F)are analyzed.The genetic characteristics of all confirmed thalassemia patients in Guangzhou were analyzed and their clinical phenotypes were analyzed.Results A total of 5207 cases were tested in Guangzhou,including 1882 cases of carriers and patients,and 27 genotypes of local poor.There were 1144 poor cases(60.79%,1144/1882),662 poor cases(35.17%,662/1882)and 76 complex poor cases(4.04%,76/1882).Among them,there were 8 globin mutations,and the most common genotype was SEA/(715,62.50%),followed by-3.7 /(270,23.60%).There were 19 mutations of globin gene,mainly cd41-42,654 and 28 M,which were 40.33%,25.38% and 12.54% respectively.Except for 2 cases of 654 homozygous gene type,all the others were pure heterozygous.Another 15 kinds of composite type of alpha composite beta to the poor,the first three-SEA/alpha alpha + 41 and42 m(20,26.32%)-alpha 3.7 / alpha alpha + 41 and 42 m(10,13.16%),-SEA/alpha alpha + 654 m(7,9.21%)Among 1144 cases of Thalassaemia,354 cases were of stationary type,509 cases of standard type,66 cases of intermediate type,and 0 cases of severe type.Of the 662 cases of thalassemia,661 cases were mild and 1 case had Hb H disease.Conclusion The dipovera gene is the most common heterozygote in the high risk population in Guangzhou,and the dipovera gene mutation is mostly heterozygous.Similar to other regions with high incidence of thalassemia in China.Part 2 Identification of the establishment of screening formulasObjectives To evaluate the effectiveness of the new identification formula(DF)in the identification of thalassemia and iron deficiency anemia;To explore the applicability of the screening formula(SF)in Guangdong province and its feasibility as a screening method for poverty.Methods A total of 2,393 cases of thalassemia and iron deficiency anemia were collected from laboratory tests conducted in the Department of Laboratory Medicine of Guangdong Hospital of Traditional Chinese Medicine from 2017 to2019.Serum iron(Fe)and serum ferritin(Fer)concentrations were determined.Relevant indicators with significant differences were screened out,and 70%of the confirmed cases randomly selected by computer were used as modeling group samples.Logistics binary regression analysis was used to establish equations,and ROC curves of different literature formulas(G&K,S&L,Jayabose,MDHL,etc.)were drawn to obtain the cut-off values of the obtained formulas.The remaining 30% of confirmed cases collected after modeling were used as the verification group,and the sensitivity,specificity and jehoden index of the 24 groups of formulas were obtained by using Medcialc statistical software and compared.Topsis was used to analyze the index parameters of 24 formulas,obtain the results of relevant Di+,Di-and proximity values(Ci),and evaluate the applicability of DF according to the size of Ci values.A total of 2,541 cases diagnosed as negative by local poverty gene were collected as the negative control group.According to the prevalence rate of local poverty in Guangzhou(17%),520 cases in the local poverty group were randomly selected as the case group,and the efficiency indicators such as missed diagnosis rate,sensitivity,specificity,likelihood ratio and odds ratio,etc.of SF used for screening indicators were calculated by using the four-grid statistical method.Results A total of 1676 samples were randomly selected from the modeling group,including 1246 cases of Thalassemia and 430 cases of iron deficiency anemia.There were significant differences in RBC,Hb,MCV and RDW between the two groups(P<0.05).According to these significantly different RBC related parameters,a new identification formula can be fitted as follows:DF=1.109×MCH-0.391×MCV+1.182×RBC+0.116×RDW.The AUC,cut-off value,sensitivity,specificity and Yoden index of IDA were 87.60%,4.08,0.803,0.807 and 0.610 respectively.Among the 24 literatures,the four formulas with the highest AUC are DF,MDHL,E&F,and G&K.The difference between DF and the other three formulas was statistically significant(P<0.05).The DF Jordan index of 0.610 is the highest of all the formulas.In the validation group,the Ci value of DF was 0.96,which was larger than other formulas.The fitting screening formula was: SF=4.27×RBC-1.309×Hb+0.54×1MCH-0.09×MCV+0.076×RDW.The accuracy of the formula is 84.71%,the AUC is 86.9%,and the cut-off value is 11.82.Youden index 0.646.The positive predictive value was 53.4% and the negative predictive value was 95.12%.The positive likelihood ratio is 5.63 and the negative likelihood ratio is 0.25.Conclusion In this study,DF was more effective than other identification formulas in the identification of Thalassaemia in Guangzhou.Compared with the identification formula of other scholars,this formula is easy to obtain,simple to calculate and can be widely used,which is suitable for other regions with high incidence of Thalassaemia.When SF is used for anemia screening,the rate of missed diagnosis is relatively low,so SF can be used as a reference indicator for the diagnosis of patients with suspected poverty in primary medical institutions. |
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