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DNA Fingerprinting

How It Is Done

Blood sample from a vein

DNA that is used to establish identity is collected from a blood sample. The health professional drawing blood will:

  • Wrap an elastic band around your upper arm to stop the flow of blood. This makes the veins below the band larger so it is easier to put a needle into the vein.
  • Clean the needle site with alcohol.
  • Put the needle into the vein. More than one needle stick may be needed.
  • Attach a tube to the needle to fill it with blood.
  • Remove the band from your arm when enough blood is collected.
  • Put a gauze pad or cotton ball over the needle site as the needle is removed.
  • Put pressure on the site and then put on a bandage.

Blood sample from a heel stick

If a DNA blood test is done on a baby, a heel stick will be done instead of a blood draw from a vein.

For a heel stick blood sample, several drops of blood are collected from the heel of the baby. The skin of the heel is cleaned with alcohol and then pricked with a small, sterile lancet. Several drops of blood are collected inside circles on a specially prepared piece of paper. When enough blood has been collected, a gauze pad or cotton ball is placed over the puncture site. Pressure is applied to the puncture site briefly and then a small bandage is usually placed over it.

Other methods

DNA can be collected from dried blood, skin, saliva, hair, urine, and semen. Bone and teeth samples are used when a body is badly decomposed.

WebMD Medical Reference from Healthwise

Last Updated: August 07, 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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