Maternal serum screening is a noninvasive method. Its principle is to assay mother’s blood for multiple biochemical, markers and calculating the risk upon parameters measured and some other risk factors like age, previous abortions,gender,number of fetuses, previous Down Syndrome pregnancies and some other behavioural and cultural paremeters. There are some different tests for predicting Down’s syndrome with noninvasive maternal blood and fluid samples dependent or independent of gestational week. One of these are quadruple test.
Interpretation: This test is done at 15-16 weeks of pregnancy but 14-22 weeks is exceptable. This test uses only second trimester markers which are AFP, bHCG, uE3 and Inhibin A. Low AFP and uE3 and high Inhibin A and bHCG is a indicator of Down’s Syndrome pregnancy High AFP also reflect spina bifida or anencephaly. Down’s Syndrome risk above 1/150 will be offered amniocynthesis. If it is lower than 1/150 amniocynthesis will not be offered If AFP is low as 2.5 times the average the result will be suspected of Open Neural Tube defect and should be examined by ultrasound. This test also gives information about Edward’s Syndrome (Trisomy 18) by using AFP, uE3 and hCG.If the risk is reported a higher than 1/100, ultrasound and amniocynthesis may be performed. Detection rate (DR) is %80 meaning %80 of the women will receive positive results.The remaining %20 may have a negative result but still may have Down Syndrome pregnancy. False Positive Rate (FPR), is %3.5 women whose pregnancies affected with Down Syndrome will receive a screen positive result meaning that although pregnancy is not a Down’s syndrome pregnancy they will still receive a screen positive result. %96.5 of the women with screen negative result will not have Down Syndrome pregnancies. Odds of being affected given a positive result(OAPR) is 1:15 meaning , among women with screen positive group,1 woman will have effected pregnancy for every 15 women who do not.
Sample: Arm vein blood.Nonfasting
Working day: Everyday
Result Time: 3 days 6:00 PM
