As of October 21, 2024, The Down syndrome screen positive cut-off for Nuchal Translucency + Second Trimester Screening  (NT + STS) has been changed to 1:350 to align with other screening tests. This screening modality is used primarily for "vanishing twin" pregnancies. The cut-off adjustment aims to enhance consistency across the system, without impacting  your prenatal practice. 

The trisomy 18 screening cut-off remains unchanged at 1:200. 

For any questions, please contact our Information Line.