Abstract:

To explore the feasibility of the dried blood specimen methods to screen Down's syndrome among midterm pregnant women. MethodsThe levels of serum Alphafetoprotein（AFP）and free betahuman chorionic gomadotropi (βhCG) in dried blood specimens on filter paper were detected with the method of timeresolved fluoroimmunoassay. The variation coefficient, recovery rate and detection limit were estimated. ResultsWhen the method was used to test AFP， the variation coefficient, recovery rate and detection limit were 2.5%64.8%, 95.1% and 0.5?u/mL respectively. When the method was used to test βhCG, the corresponding results were 4.1%7.0%, 97.6% and 1?U/mL respectively. The onset risk rate was 1/128, with an accordance rate of 98.4% compared with that of the gold standard of serum screening method which is universally accepted. A total of 1?320 pregnant women were tested in this study, and 85 positive cases(6.4% )were screened out. One fetus was diagnosed as having Down′s syndrome by detecting the chromosomes in the amniotic fluid. ConclusionsThe method of timeresolved fluoroimmunoassay through dried blood specimen, in place of the serum method, to detect the levels of AFP and βhCG among midterm pregnant women is convenient and feasible and its screening result is accurate and reliable.

Key words:  Dried blood spots specimen on filter paper; Down′s syndrome; Alpha fetoprotein; Free betahuman chorionic gomadotropi