The Brain and Spine Institute is made up of experts in the field of neuroscience in order to bring patients the best healthcare in East Tennessee for a full range of neurological diseases and disorders.
myClipboard
myClipboard
Save news, events, articles and doctor's information to your personal clipboard for later reference.
Add items by clicking the 
button.
Create an account
Centers of Excellence
-
-
We provide a comprehensive continuum of cancer services, including prevention, outreach, diagnostic, treatment and support services delivered by our highly skilled staff with compassion and care.
-
The Center for Women & Children's Health is a hub for supporting women's and children's individual healthcare needs. The center provides support, research and unmatched patient-centered care.
-
Emergency and Trauma Services is the only Level I Trauma Center in the area and serves as the tertiary referral center for medical care in East Tennessee, serving Knox County and 21 surrounding counties.
-
The Heart Lung Vascular Institute brings together expertise in clinical care, teaching and research. Patients receive exceptional healthcare combined with patient-centered care.
Share
Print
Related Media
Karyotyping
Definition
Karyotyping is a test to examine chromosomes in a sample of cells, which can help identify genetic problems as the cause of a disorder or disease. This test can:
- Count the number of chromosomes
- Look for structural changes in chromosomes
Alternative Names
Chromosome analysis
How the test is performed
The test can be performed on almost any tissue, including:
- Amniotic fluid
- Blood
- Bone marrow
- Tissue from the organ that develops during pregnancy to feed a growing baby (placenta)
To test amniotic fluid, an amniocentesis is done.
A bone marrow specimen requires a bone marrow biopsy.
The sample is placed into a special dish and allowed to grow in the laboratory. Cells are later taken from the growing sample and stained. The laboratory specialist uses a microscope to examine the size, shape, and number of chromosomes in the cell sample. The stained sample is photographed to provide a karyotype, which shows the arrangement of the chromosomes.
Certain abnormalities can be identified through the number or arrangement of the chromosomes. Chromosomes contain thousands of genes that are stored in DNA, the basic genetic material.
How to prepare for the test
There is no special preparation needed.
How the test will feel
How the test will feel depends on whether the sample procedure is having blood drawn (venipuncture), amniocentesis, or bone marrow biopsy.
Why the test is performed
This test is usually done to evaluate a couple with a history of miscarriages, or to examine any child or baby who has unusual features or developmental delays that suggest a genetic abnormality.
The bone marrow or blood test can be done to identify the Philadelphia chromosome, which is found in about 85% of people with chronic myelogenous leukemia (CML).
The amniotic fluid test is done to check a developing fetus for chromosome abnormalities.
Normal Values
- Females: 44 autosomes and 2 sex chromosomes (XX), written as 46, XX
- Males: 44 autosomes and 2 sex chromosomes (XY), written as 46, XY
What abnormal results mean
Abnormal results may be due to a genetic syndrome or condition, such as:
- Down syndrome
- Philadelphia chromosome
- Trisomy 18
This list is not all-inclusive.
Additional conditions under which the test may be performed:
- Chronic myelogenous leukemia (CML) or other leukemias
- Developmental delays
- Multiple birth defects
What the risks are
The risks are related to the procedure used to obtain the specimen.
See:
In some cases, an abnormality may occur as the cells as growing in the lab dish. Karyotype tests should be repeated to confirm that an abnormal chromosome problem is actually in the body of the patient.
Special considerations
Chemotherapy may cause chromosome breaks that affect normal karotyping results.
See also: Mosaicism
Your doctor may also order other tests that go together with a karyotype:
- Telomere studies -- look at the ends of the chromosomes
- Microarray -- looks at small changes in the chromosomes
- Fluorescent in situ hybridisation (FISH) -- looks for small mistakes such as deletions in the chromosomes
A.D.A.M., Inc. is accredited by URAC, also known as the American Accreditation HealthCare Commission (www.urac.org). URAC's accreditation program is an independent audit to verify that A.D.A.M. follows rigorous standards of quality and accountability. A.D.A.M. is among the first to achieve this important distinction for online health information and services. Learn more about A.D.A.M.'s editorial policy, editorial process and privacy policy. A.D.A.M. is also a founding member of Hi-Ethics and subscribes to the principles of the Health on the Net Foundation (www.hon.ch).