Down Syndrome Screening

Down Syndrome or Trisomy 21, is one of the most common autosomal chromosomal aberration of the newborn. The severity of the syndrome includes, mental deficiency, congenital cardiac malformation, immune system disorders, gastrointestinal malformation and slow physical development. This test uses only the first trimester markers, NT and PAPP-A. The perfect gestational week is around 11, but 10-13 is acceptable. When blood sample is obtained, an ultrasound should be performed on the same day.
Interpretation:(Should be done by the clinician) Low PAPP-A, high NT, free bHCG will be an indicator of DOWN’s syndrome pregnancy This test does not give information about the neutal tube defects. If the risk comes out as 1/150 or over, an amniosynthesis or CVS (Chorionic Vilus Sampling) may be offered. If the risk of Edward’s syndrome is 1/100, an ustrasound scan will be offered (detection rate %85, FPR: %0.2). The Down’s Syndrome deteciton rate is %84 80, meaning, %84.8 of the women will receive positive results. The remaining %15.8, may have a negative result but still may have Down Syndrome pregnancy. FPR is %2.2,meaning that, although pregnancy is not a Down’s syndrome pregnancy, %2.2 pregnants will still receive a screen positive result. OAPR is 1:9, meaning, among women with screen positive group, 1 woman will have effected pregnancy for every 9 women who do not.
Sample: Arm vein blood. Nonfasting
Working day: Everyday
Result Time: 2 days 6:00 PM