Each sample, such as blood, is set up in duplicate cultures for chromosome analysis, so results are reliable and reproducible.
How the test is performed
Sample collection
Blood (or another sample type) is collected in the correct container and sent to the laboratory.
Cell culture
Blood lymphocytes are grown in complete medium with the mitogen phytohaemagglutinin (PHA) to stimulate cell division, usually for 72 hours.
Harvest & G-banding
Dividing cells are harvested and chromosomes are stained using G-banding to reveal their characteristic band patterns.
Microscopy & imaging
Chromosomes are studied under bright-field microscopy and photographed for analysis.
Analysis & report
Numerical and structural abnormalities, including balanced and unbalanced translocations, are analysed using GenASIs BandView software (Applied Spectral Imaging) and reported.
Process flow chart
Example karyotypes
Figure 1 – Normal male karyotype. Stained chromosomes are photographed for study. A normal set has 46 chromosomes in 23 pairs, one chromosome of each pair from each parent.
Figure 2 – Abnormal female karyotype. An extra copy of chromosome 21 (trisomy 21) causes Down syndrome.
Methodology
Conventional cell culture
Duplicate PHA-stimulated lymphocyte cultures.
G-banding
High-quality banding for structural analysis.
Bright-field microscopy
Detailed study of metaphase chromosomes.
BandView analysis
Software-assisted detection of numerical and structural abnormalities.