Karyotype Test

Karyotype Test

Guide

Results

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.

Karyotype

Normal:	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 chromosome.
Abnormal:	There are more than or fewer than 46 chromosomes. The shape or size of one or more chromosomes is abnormal. A chromosome pair may be broken or incorrectly separated.

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 tests.
• Sometimes a karyotype test is combined with other genetic tests to provide more specific information about genetic problems. To learn more, see the topic Genetic Test.

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 Staff
Primary Medical ReviewerKathleen Romito, MD - Family Medicine
Specialist Medical ReviewerSiobhan M. Dolan, MD, MPH - Reproductive Genetics