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Health & Pregnancy

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Genetic Test


A genetic test examines the DNA (deoxyribonucleic acid) of a person's cells. Genetic testing can identify changes in genes or can analyze the number, arrangement, and characteristics of the chromosomes.

The results of genetic testing depend on the type of test done. Genetic testing is used to:

  • Diagnose an inherited disease.
  • Provide information about how likely it is that you will develop a disease in the future.
  • Determine whether you are a carrier of the disease.
  • Provide information about the severity of an inherited disease.
  • Help choose appropriate treatment for some diseases, such as HIV infection or some types of cancer.

What Affects the Test

Having a blood transfusion within a week before the test can interfere with your test or the accuracy of the results.

What To Think About

The information obtained from a genetic test can have a profound impact on your life. Genetic counselors are trained to help you understand your risk for having a child with an inherited (genetic) disease, such as sickle cell disease, cystic fibrosis, or hemophilia. A genetic counselor can help you make well-informed decisions. Ask to have genetic counseling before making a decision about genetic testing.

  • A genetic test result is sensitive information. Your confidentiality should be maintained, and the release of information should be limited to those who are authorized to receive it.
  • The discovery of a genetic disease that is not causing symptoms now (such as breast cancer or Huntington's disease) should not affect your future ability to gain employment or health insurance coverage. A law in the United States, called the Genetic Information Nondiscrimination Act of 2008 (GINA), protects people who have DNA differences that may affect their health. This law does not cover life insurance, disability insurance, or long-term care insurance.
  • A genetic test can sometimes reveal unintended information, such as the identity of a child's father (paternity).
  • A fetal genetic test may detect a serious disease or disorder (such as Down syndrome) that will greatly impact your child's life and the lives of caregivers. A pregnant woman who is considering genetic testing may want to consider her ethical, social, and religious beliefs to help her determine the actions she would take if test results are positive.
  • A karyotype can be used to examine the size, shape, and number of chromosomes. Extra or missing chromosomes, or abnormal positions of chromosome pieces, can cause problems with a person's growth, development, and body functions. To learn more, see the topic Karyotype Test.
  • A breast cancer (BRCA) gene test is done to evaluate your risk of developing breast cancer. To learn more, see the topic Breast Cancer (BRCA) Gene Test.
  • A type of genetic test (DNA fingerprinting) can be used to determine paternity, help solve crimes, and identify a body. DNA fingerprinting is more accurate than dental records, blood type, or traditional fingerprints. To learn more, see the topic DNA Fingerprinting.

WebMD Medical Reference from Healthwise

Last Updated: March 12, 2014
This information is not intended to replace the advice of a doctor. Healthwise disclaims any liability for the decisions you make based on this information.

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