A procedure in which a small amount of amniotic fluid is removed through a needle from the fetal sac at about 16 weeks pregnancy. The fluid is studied for chromosomal abnormalities that may affect fetal development.

A chromosome abnormality in the number of chromosomes. Typically there are pairs (2) of chromosomes. A change to this number (more or less) often results in a miscarriage or genetic disorder to the child. For example, trisomy 21 (three chromosome 21s) causes Down’s syndrome.

A karyotype showing an aneuploidy of chromosome 21.

A Y-shaped protein, naturally in blood, used by the immune system. It is specific for binding (like a perfect puzzle piece) to another substance (see “antigen”). Antibodies are made when the body detects something foreign to destroy (ie. bacteria, viruses). They can also play a role in the lab for detection assays.

Something foreign or toxic detected by the body. The body creates proteins that will bind to these to flag it to be destroyed (see “antibody”).

Array-Comparative Genomic Hybridization (aCGH)
CGH is is a method for analyzing regions of chromosomes to determine aberrations in the number of copies, by comparing to a control reference. When an array is used (aCGH), it can detect smaller differences and is therefore more specific. aCGH was originally used for Preimplantation Genetic Screening/Diagnosis (PGS/PGD, now PGT-A/PGT) by MSS. See “chromosomes” and “microarray”.

A laboratory term for a test.