Research And Design Of Test System Of Prenatal Screen For Down's Syndrome

There are many fetuses suffering from Down's syndrome in our country. In order to improve our newly born babies' quality and reduce birth rates of Down's syndrome, the work of prenatal screen for Down's syndrome need to be developed urgently. However, this work in our country mainly depends on the foreign equipments of prenatal screen for Down's syndrome and the foreign equipments have many disadvantages which are not suitable for many hospitals at the basic level, such as high price, hard operation, test only in the condition of many maternal serums, so it hasn't been developed nationwide until now.In view of the above reasons, a new idea that Quantitive test of gold immunochromotographic assay (GICA) is applied to prenatal screen for Down's syndrome is put forward in this paper and the test system of prenatal screen for Down's syndrome is designed. The signal of colloidal-gold strips are converted from light into electricity and then processed, modeled by computer. In the end the risk rate of Down's syndrome can be got by calculating with the software of prenatal screen for Down's syndrome. This system has many advantages, such as low price, easy operation, individual test and so on. So it can be use widely in hospitals at the basic level in our country.The main research work in this paper is as follows:(1) Introduce Down's syndrome and the current situation of prenatal screen for Down's syndrome in the world briefly.(2) After compared with other technology of quantitive test in prenatal screen for Down's syndrome in the world, the quantitive test of GICA that suits the current situation of our country is applied to the test system of prenatal screen for Down's syndrome.(3) The thickness change of the sample that is needed testing is converted into color change of test line in the colloidal-gold strip by GICA. And then the sensing device of photoelectricity based on CCD is designed to convert the change of color into the change of the electric signal.(4) After reduced noise by the hardware circuit, CCD signal enter DSP where the signal is converted from analog to digital. Then its noise is reduced again by median filtering. And then the location of test line is identified by wavelet of Haar. Finally the opticaldensity of test signal can be got.(5) Cubic spline is adopted to approach the curve of the relation between standard thickness and optical density in order to establish the model of them.(6) The optical density from hardware part of system is sent to computer through serial port and converted into thickness by the established model. According the thickness of the sample and the characteristic of Down's syndrome, the software of prenatal screen for Down's syndrome is designed which has many functions, such as analysing synthetically, saving, printing, presenting reports, and so on.(7) In order to examine the accuracy of the system's test result, over one hundred clinical tests are carried on in the maternity & child care center of Jining city. The results accord with reality comparatively well, so this system has certain practicability.