Apollo Diagnostics

Chromosome test procedure

Chromosome test procedure

The test is performed by:

Taking a sample of a person’s cells, culturing them in nutrient-enriched media to promote cell division in vitro. This is done in order to select a specific time during the cells’ growth phase when the chromosomes are easiest to distinguish.
Isolating the chromosomes from the nucleus of the cells, placing them on a slide, and treating them with a special stain.
Taking microphotographs of the chromosomes.
In jigsaw puzzle fashion, rearranging the pictures of the chromosomes to match up pairs and arrange them by size, from largest to smallest, numbers 1 to 22, followed by the sex chromosomes as the 23rd pair.
The pictures also allow the chromosomes to be vertically oriented. Each chromosome looks like a striped straw. It has two arms that differ in length (a short arm (p) and a long arm (q)), a pinched-in area between the arms called a centromere, and a series of light and dark horizontal bands. The length of the arms and the location of the bands help determine top from bottom.
Once the chromosome photo arrangement is completed, a laboratory specialist evaluates the chromosome pairs and identifies any abnormalities that may be present.

A blood sample is obtained by inserting a needle into a vein in the arm.
Amniotic fluid and chorionic villi are collected from a pregnant woman by a healthcarce practitioner using amniocentesis or chorionic villus sampling procedures.
Bone marrow or tissue sample collections require a biopsy procedure to be performed