Prenatal diagnosis is used for discovery of pregnant mothers' fetus abnormalities, ranging from maternal serum screening, cytogenetic analysis for chromosome karyotypes, to molecular genetic diagnosis. It is therefore the primary approach to prevent and reduce birth defects. Based on the experience obtained from developed countries, large-scale prenatal diagnosis has been carried out in China, including maternal serum screening for Down syndrome, prenatal diagnosis of chromosomal diseases, and certain gene analysis for genetic diseases. However, it is noted that such development is uneven in different regions. As a great disease-prevention project involving steady development of the nation and the ethnic groups, it is still necessary to establish or improve the prenatal diagnosis system and quality management regulations that are fit for the domestic conditions of China.

It must be emphasized in the maternal serum prenatal screening that the quality is not only influenced by accuracy of biomarker assay,risk calculation parameters and biomarker database,but also influenced by clinical factors such as gestational weeks,weight and ect.The result of prenatal screening is just a risk evaluation,the subsequent diagnosis and the follow-up are more important.It is expected to improve screening efficiency by localization of prenatal screening database and making the quality management of the prenatal screening-diagnosis suitable for the national conditions.On the other hand,prenatal screening in the women of advanced maternal age and twin pregnancy,improve amniotic fluid cell culture method,chromosome analysis automation,the introduction and positioning of rapid prenatal molecular diagnosis techniques become the hot issues.

Objective To establish D-dimer normal reference range in pregnant and postpartum women in Zhejiang Han population.Methods Plasma samples were collected from 669 healthy pregnant women, 578 healthy postpartum women, 8 venous thrombosis or DIC patients and 80 healthy non-pregnant women in Women′s Hospital, School of Medicine, Zhejiang University from March 2009 to August 2010.According to different gestational week, postpartum days and delivery pattern, the healthy pregnant and postpartum women were stratified into 3 groups: (1) ≤13 weeks (n=120), 14-20 weeks (n=120), 21-27 weeks (n=145), 28-34 weeks (n=147), ≥35 weeks (n=137);(2) The first day after vaginal delivery (n=163), the second day after vaginal delivery (n=121);(3) The first day after cesarean sections (n=166), the second day after cesarean sections (n=128). These groups were further stratified based on age: ＜30 years old and ≥30 years old.All blood samples were drawn in citrate sodium anticoagulated blood.D-dimer concentration was determined by STA-R Evolution coagulation analyzer.Since D-dimer concentration showed non-normal distribution, the normal values (one-tailed) were established by using (P95) percentile method.The results of 8 patients were used to validate the established normal values.Results In the group of ＜30 years old, the D-dimer values[M(P25-P75)]in group of ≤13 weeks, 14-20 weeks, 21-27 weeks, 28-34 weeks, ≥35 weeks and healthy non-pregnant women were 0.25(0.17-0.37), 0.51(0.38-0.75), 0.75(0.57-1.10), 1.14(0.80-1.48), 1.60(1.14-1.89) and 0.20(0.10-0.28) mg/L, respectively, which showed statistical difference(H=239.24, P＜0.05).In the group of ≥30 years old, the D-dimer values of the above different groups were 0.28(0.14-0.38), 0.50(0.36-0.65), 0.83(0.59-1.41), 0.93(0.68-1.37), 1.47(1.22-1.84) and 0.17(0.12-0.25) mg/L, respectively, which also showed statistical difference(H=127.75, P＜0.05).In the group of ＜30 years old, the D-dimer values were 2.45(1.51-3.77), 1.30(0.97-1.96), 2.68(1.52-3.74) and 1.55(1.10-2.10) on the first and second day after vaginal delivery and cesarean section, respectively, which showed statistical difference (H=64.85,P＜0.05).In the group of ≥30 years old, the corresponding values were 2.20(1.33-3.54), 1.33(1.02-2.14), 2.27(1.66-3.17) and 1.62(1.26-2.69), respectively, which also showed statistical difference(H=18.64, P＜0.05).D-dimer normal values were established based on different gestational week, postpartum days and delivery pattern.The normal values of ≤13 weeks, 14-20 weeks, 21-27 weeks, 28-34 weeks and ≥35 weeks were ≤0.64 mg/L, ≤1.54 mg/L, ≤2.60 mg/L, ≤3.01 mg/L and ≤3.19 mg/L, respectively. The normal values of 1st day after vaginal delivery, 2nd day after vaginal delivery,1st day after cesarean sections and 2nd day after cesarean sections were ≤7.83 mg/L, ≤3.29 mg/L, ≤9.95 mg/L and ≤3.80 mg/L.All 8 patients showed positive results with the above normal values.Conclusion D-dimer normal values in pregnant and postpartum women in Zhejiang Han population are established, which can improve the application values of D-dimer in the pregnant and postpartum population.

Objeetive To evaluate the performance characteristics of the second trimester double test for the detection of fetal Down's syndrome(DS)in women of advanced maternal age(AMA).Methods We undertook a prospective nation-wide multi-centered study and chose alpha-fetoprotein(AFP))and free β-subunit of human chorionic gonadotrophin(free β-hCG)as the serum markers.Between May 2004 and September 2006,12 centers participated in the collection and analysis of maternal serum AFP and free β-hCG.Patients with an iuereaged risk of DS(≥1/270)wero offered generic sunniocentesis.Follow up of the outcome of all pregnancies was obtained.Patients were divided into two groups,the AMA group and the non-AMA group and the screening efficiency Was evaluated in beth groups.Results A total of 66 132 singleton pregnancies were included in the study.and there were 36 10(5.46%)AMA women.The median maternal age of AMA women was 36.8years(35-47 years).At a cut-off of 1/270,in the AMA group,the number of positive cases screened was 727 and 22 cases of fetal DS were detected:the number of negative cases screened was 2883,and no fetal DS was found.In the non-AMA group,the number of positive cases screened was 4743 and 69 cases of fetal DS were detected:the number of negative cases screened was 57 779,and 6 cases of fetal DS were diagnosed postnatally.In AMA group,the detection rate(DR),false positive rate(FPR)and odds of being affected given a positive result(OAPR)were 100%,19.7%and 3.0%respectively.In the non-AMA group,the DR,FPR and OAPR were 92.0%.7.5%and 1.5%respectively.Conclusion The double-marker test using AFP and free β-hCG is an effective screen strategy for second-trimester detection of Down syndrome in AMA women.

Objective:To study the application value of practical demonstration of actual X-ray film images in the experimental teaching of radiography technology courses in medical imaging undergraduates.Methods:A total of 63 medical imaging undergraduates of Grade 2015 were randomly divided into three groups to receive part of the experimental courses about chest and abdomen radiography examination. Their pre-class work and machine were the same. As the experimental group, group A and group B added demonstration with X ray film images, while group C (control group) did not. The different teaching effects of the two methods were evaluated by simulate practical assessment and quiz. The accepting degree of demonstration method was evaluated in accordance with questionnaire survey.Results:The scores of simulated practical assessment (7.36±1.39) and quiz (4.24±2.01) in experimental group were significantly higher than those of (6.05±1.28) and (3.10±1.48) in the control group, with a statistically significant difference ( P<0.01, P=0.024). Questionnaire survey showed that the experimental group were 100% accepted practical demonstration of X ray film images. Conclusion:The application of practical demonstration of X-ray film images in radiology technology experimental courses can help undergraduates to accept new knowledge, deepen impression on knowledge and improve teaching effect, which is worth developing and popularizing.