DNA Fingerprinting

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Test Overview

DNA fingerprinting is a test to identify and evaluate the genetic information, called DNA (deoxyribonucleic acid), of a person's cells. It is called a "fingerprint" because it is very unlikely that any 2 people would have exactly the same cellular information, in the same way that it is very unlikely that any 2 people would have exactly the same physical fingerprint. The test is used to determine whether a family relationship exists between two people, to identify organisms causing a disease, and to solve crimes.

Only a small sample of cells is needed for DNA fingerprinting. A drop of blood or the root of a hair contains enough DNA for testing. Semen, hair, or skin scrapings are often used in criminal investigations. See a picture of DNA testing in a criminal investigation .

A person who has DNA fingerprinting done voluntarily usually provides a sample of blood taken from a vein. DNA testing also can be done on cells obtained by a simple mouthwash or a swab of the cheeks inside the mouth, but these methods are not recommended.

Last updated:	April 26, 2007
Author:	Maria G. Essig, MS, ELS
Reviewed By:	Joy Melnikow, MD, MPH - Family Medicine, Renee H. Martin, PhD - Medical Genetics
Editors:	Susan Van Houten, RN, BSN, MBA, Tracy Landauer