Diagnosis of Down syndrome at or after birth

If physical examination of the child at birth or in early infancy suggests Down syndrome (see Clinical characteristics of Down syndrome), liaise with a paediatrician for urgent referral and advice on other assessments (eg cardiac ultrasound) that may be performed while awaiting review. Diagnostic tests performed after birth include:

• chromosome microarray—confirms the presence of extra copy of chromosome 21 and detects mosaic Down syndrome, but cannot distinguish translocation Down syndrome from conventional trisomy 21; results are available after 1 to 2 weeks
• rapid blood test (FISH)—confirms the presence of extra material from chromosome 21; results are available within a few days
• karyotype—provides further information on the type of Down syndrome; results are available after 1 to 2 weeks.

For advice on discussing a developmental disability diagnosis with parents, see here. See also Support for carers and family of people with developmental disability.