Karyotype is a test to identify and evaluate the size, shape, and number of chromosomes in a sample of body cells. Extra or missing chromosomes, or abnormal positions of chromosome pieces, can cause problems with a person's growth, development, and body functions.
is done to:
You do not need to do anything before you have this test.
Talk to your doctor about any concerns you have about the need for the test, its risks, or how it will be done. To help you understand the importance of this test, fill out the medical test information form(What is a PDF document?).
Since the information obtained from karyotyping can have a profound impact on your life, you may want to see a doctor who specializes in genetics (geneticist) or a genetic counsellor. This type of counsellor is trained to help you understand what karyotype test results mean for you, such as your risk for having a child with an inherited (genetic) condition like Down syndrome. A genetic counsellor can help you make well-informed decisions. Ask to have genetic counselling before making a decision about a karyotype test.
Karyotype testing can be done using almost any cell or tissue from the body. A karyotype test usually is done on a blood sample taken from a vein. For testing during pregnancy, it may also be done on a sample of amniotic fluid or the placenta.
The health professional drawing your blood will:
For this type of test, cells are collected from the fetus using amniocentesis or chorionic villus sampling.
For more information about amniocentesis, see:
Bone marrow aspiration
may be used for a karyotype test. To learn more about how this test is done, see the topic Bone Marrow Aspiration and Biopsy.
You may feel nothing at all from the needle puncture, or you may feel a brief sting or pinch as the needle goes through the skin. Some people feel a stinging pain while the needle is in the vein. But many people do not feel any pain, or have only minor discomfort, once the needle is positioned in the vein. The amount of pain you feel depends on the skill of the health professional drawing the blood, the condition of your veins, and your sensitivity to pain.
There is very little chance of a problem from having a blood sample taken from a vein.
Karyotype is a test to identify and evaluate the size, shape, and number of chromosomes in a sample of body cells.
Results of a karyotype test are usually available within 1 to 2 weeks.
If you are being treated for cancer, the results of a karyotype test may not be accurate. Chromosomes may be damaged by some types of cancer treatment.
Other Works Consulted
Chernecky CC, Berger BJ (2008). Laboratory Tests and Diagnostic Procedures, 5th ed. St. Louis: Saunders.
Fischbach FT, Dunning MB III, eds. (2009). Manual of Laboratory and Diagnostic Tests, 8th ed. Philadelphia: Lippincott Williams and Wilkins.
Pagana KD, Pagana TJ (2010). Mosby’s Manual of Diagnostic and Laboratory Tests, 4th ed. St. Louis: Mosby.
Skirton H, Patch C (2009). Genetics for the Health Sciences: A Handbook for Clinical Healthcare, 2nd ed. Oxfordshire, UK: Scion Publishing.
ByHealthwise StaffPrimary Medical ReviewerKathleen Romito, MD - Family MedicineDonald Sproule, MDCM, CCFP - Family MedicineMartin J. Gabica, MD - Family MedicineE. Gregory Thompson, MD - Internal MedicineAdam Husney, MD - Family MedicineSpecialist Medical ReviewerSiobhan M. Dolan, MD, MPH - Reproductive Genetics
Current as ofOctober 13, 2016
Current as of: October 13, 2016
Kathleen Romito, MD - Family Medicine
& Donald Sproule, MDCM, CCFP - Family Medicine & Martin J. Gabica, MD - Family Medicine & E. Gregory Thompson, MD - Internal Medicine & Adam Husney, MD - Family Medicine & Siobhan M. Dolan, MD, MPH - Reproductive Genetics
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