Karyotype testing is a type of genetic testing that examines the size, shape, and number of chromosomes in a sample of cells from the body. Chromosomes are the parts of our cells that contain genes, which consist of DNA. The test can help identify genetic problems as the cause of a disorder or disease. Karyotype testing may be used to:
- Check for unusual changes in chromosomes
- Check for specific chromosome problems if you have a genetic disorder that runs in your family or have symptoms that may be from a genetic disorder
- Check an unborn baby for chromosome problems
- Find out if abnormal chromosomes are causing problems having children, including male or female infertility
- Diagnose certain cancers or blood disorders that often involve changes in chromosomes
During a karyotype test, the type of sample you provide depends on the reason for the test. The sample may be gathered using a blood test, a buccal (cheek) swab, or other methods. The sample is then sent to a laboratory where cells are taken from the sample and stained. A laboratory specialist uses a microscope to examine the size, shape, and number of chromosomes in the cell sample. The stained sample is photographed to show the arrangement of the chromosomes, which is called a karyotype.
Karyotype testing can help identify genetic disorders and guide treatment, but it can also have profound emotional effects. Some people choose to talk with a genetic counselor before having a karyotype test. The risks of the procedure used to obtain the sample are generally low, but in some cases, a problem may occur in the cells growing in the lab dish. Karyotype tests should be repeated to confirm that an abnormal chromosome problem is actually present.
