Cytogenetic examination is used to determine the karyotype of a person, i.e. to determine the chromosomal equipment of a cell.
The karyotype can be determined both prenatally and after birth. Prenatally, for division of the cell we use foetal cells obtained from the amniotic fluid or placental cells or less commonly foetal blood cells obtained from the umbilical blood. We perform a postnatal cultivation of venous blood.
Our laboratory is accredited according to ČSN EN ISO 15189.
The chromosomes achieve maximum density, i.e. their shape is best differentiated in the metaphase of the mitotic cycle. By stopping the division we obtain a preparation that is ready for reading the karyotype under the microscope. Each chromosome is specifically stained and looks like light and dark bands (G-bands).
The chromosomes are evaluated using a light microscope We calculate the chromosomes and then evaluate their structure. The single chromosomes are marked with the numbers 1-22, the sex chromosomes with the letters X and Y. We look at the distribution of the light and dark bands and their size and colour intensity. The human karyotype has 46 chromosomes, 22 pairs (one set from the father, one from the mother) are identical for man and woman while the sex chromosomes are different.
A deviation in the amount or structure of the chromosomes is considered as a pathological finding.