Chromosome 21 Aneuploidy [Presence] in Amniotic Fluid or Chorionic Villus Sample by FISH

**Semantic type:** Laboratory Procedure

**Definition:** A nominal fluorescent in situ hybridization-based procedure that detects chromosome 21 aneuploidy in an amniotic fluid or chorionic villus specimen.

**Synonyms:** - Chromosome 21 aneuploidy [Presence] in Amniotic fluid or Chorionic villus sample by FISH