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
- There are 46 chromosomes that can be
grouped as 22 matching pairs and 1 pair of sex chromosomes (XX for a female and
XY for a male).
- The size, shape, and structure are normal for each
- There are more than or fewer than 46
- The shape or size of one or more chromosomes is
- A chromosome pair may be broken or incorrectly
What Affects the Test
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.
What To Think About
- If the results of karyotype
are abnormal, other family members may be advised to have the test.
- A sample taken by gently swabbing the tissues inside the cheek
(called a buccal swab) sometimes is used for a karyotype test. But results from
buccal swabbing are less accurate than other types of karyotype
- Sometimes a karyotype test is combined with
other genetic tests to provide more specific information about genetic
problems. To learn more, see the topic
Other Works Consulted
Chernecky CC, Berger BJ (2008). Laboratory Tests and Diagnostic Procedures, 5th ed. St. Louis:
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.
Primary Medical ReviewerKathleen Romito, MD - Family Medicine
Specialist Medical ReviewerSiobhan M. Dolan, MD, MPH - Reproductive Genetics
Current as ofMarch 12, 2014