Terrence Hallahan

First trimester Down syndrome screening with dried blood spots using a dual analyte free beta hCG and PAPP-A immunofluorometric assay.

To determine the effectiveness of first trimester Down syndrome screening with dried blood spots using a dual analyte free beta human chorionic gonadotrophin (hCG)/pregnancy‐associated plasma protein A (PAPP‐A) immunofluorometric assay.

First-trimester screening in triplets

OBJECTIVEnThe purpose of this study was to determine the performance of Down syndrome screening in triplet pregnancy.nnnSTUDY DESIGNnNuchal translucency (NT; n = 794), nasal bone (n = 219), and biochemistry (n = 198) were evaluated in triplet pregnancy. Screening performance was evaluated with the use of delta and Gaussian models.nnnRESULTSnThe median multiples of the median values for free beta human chorionic gonadotropin and pregnancy-associated plasma protein A were 2.86 and 3.48, respectively. A significant correlation in delta NT within pregnancy was observed (0.46-0.68). The modeled false-positive rates were 11.7%, 7.4%, and 8.9% with the delta model and 11.9%, 6.6%, and 12.0% with the Gaussian model for NT, NT + nasal bone, and NT + biochemistry. Based on simulation, the detection rate at 12 weeks gestation was 78%, 93%, and 80% for NT, NT + nasal bone, and NT + biochemistry at a 10% false-positive rate using either the delta or Gaussian models.nnnCONCLUSIONnIn triplet pregnancy, the addition of nasal bone lowers the false-positive rate of nuchal translucency screening. More data are required on the effectiveness of biochemistry.

Screening for Open Neural Tube Defects

Biochemical prenatal screening was initiated with the use of maternal serum alpha fetoprotein to screen for open neural tube defects. Screening now includes multiple marker and sequential screening protocols involving serum and ultrasound markers to screen for aneuploidy. Recently cell-free DNA screening for aneuploidy has been initiated, but does not screen for neural tube defects. Although ultrasound is highly effective in identifying neural tube defects in high-risk populations, in decentralized health systems maternal serum screening still plays a significant role. Abnormal maternal serum alpha fetoprotein alone or in combination with other markers may indicate adverse pregnancy outcome in the absence of open neural tube defects.

Incorporation of dried blood alpha fetoprotein into traditional first trimester Down syndrome screening service

The aim of this study was to determine whether incorporation of dried blood alpha fetoprotein (AFP) into first trimester screening using the biochemical markers free Beta human chorionic gonadotropin (hCG) and pregnancy‐associated plasma protein A (PAPP‐A) can improve screening performance.