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:
The test can be performed on a sample of blood, bone marrow, amniotic fluid, or tissue from the placenta, the organ that develops during pregnancy to feed a growing baby.
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.
There is no special preparation needed.
How the test will feel depends on whether the sample procedure is venipuncture (having blood drawn), amniocentesis, or bone marrow biopsy.
This test is usually done to evaluate a couple with a history of miscarriages or to examine an abnormal appearance of the body that suggests a genetic abnormality.
The bone marrow or blood test can be done to identify the Philadelphia chromosome, which is found in about 85% of those with chronic myelogenous leukemia (CML) .
The amniotic fluid test is done to check a developing fetus for chromosome abnormalities.
|
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 the first of its kind, requiring compliance with 53 standards of quality and accountability, verified by independent audit. 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 process . A.D.A.M. is also a founding member of Hi-Ethics (www.hiethics.com) and subscribes to the principles of the Health on the Net Foundation (www.hon.ch). |