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DNA Fingerprinting

Results

DNA fingerprinting is a test to identify and evaluate the genetic information—called DNA (deoxyribonucleic acid)—in a person's cells.

DNA samples can:

  • Determine who a person's parents are (establish paternity and maternity). Tissue samples from two people can also be compared to determine how likely they are to be blood relatives.
  • Determine whether a suspect was present at a crime scene, by comparing DNA from the scene to the DNA of the suspect.
  • Positively identify a body. Bone and hair samples can be used to identify a badly decomposed body.

What Affects the Test

Reasons you may not be able to have the test or why the results may not be helpful include:

  • Sample size. The possibility of having inaccurate test results increases if a very small sample of DNA is available for testing. The chance that the DNA will be mixed up with some other DNA is also higher with a smaller sample.
  • Having had a blood transfusion within the past 3 months.
  • Decay of the tissue sample.

What To Think About

  • Because DNA fingerprinting has been used to identify bodies, such as military personnel killed in action or crime victims, DNA databases (much like fingerprint databases) have been developed. DNA fingerprinting is more accurate than traditional fingerprints, dental records, blood type, or ID tags for this purpose.
  • Although home paternity test kits are available, they are not as accurate as DNA fingerprinting, and the results cannot be used in a court of law. If you are thinking about using of one of these kits, talk with your doctor.
  • Other tests that can help determine the likelihood of two people being related or that can detect inherited diseases include karyotyping and genetic testing. For more information, see the topics Karyotype Test and Genetic Test.

Other Works Consulted

  • Fischbach FT, Dunning MB III, eds. (2009). Manual of Laboratory and Diagnostic Tests, 8th ed. Philadelphia: Lippincott Williams and Wilkins.

ByHealthwise Staff
Primary Medical ReviewerKathleen Romito, MD - Family Medicine
Specialist Medical ReviewerSiobhan M. Dolan, MD, MPH - Reproductive Genetics
Last RevisedNovember 29, 2012
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WebMD Medical Reference from Healthwise

Last Updated: November 29, 2012
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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