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DNA Fingerprinting

How It Is Done continued...

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.

How It Feels

Blood sample from a vein

You may feel nothing at all from the needle puncture, or you may feel a brief sting or pinch as the needle goes through the skin. Some people feel a stinging pain while the needle is in the vein. But many people do not feel any pain, or have only minor discomfort, after the needle is positioned in the vein. The amount of pain you feel depends on the skill of the health professional drawing the blood, the condition of your veins, and your sensitivity to pain.

Blood sample from a heel stick

The baby may feel a brief sting or a pinch when the lancet pricks the skin. While the blood is being collected, there is very little or no discomfort.

The collection of DNA from saliva, urine, or semen does not cause discomfort.

Risks

Blood sample from a vein

There is very little chance of a problem from having a blood sample taken from a vein.

  • You may get a small bruise at the puncture site. You can lower the chance of bruising by keeping pressure on the site for several minutes.
  • In rare cases, the vein may become swollen after the blood sample is taken. This condition is called phlebitis. You can use a warm compress several times daily to treat this.
  • Ongoing bleeding can be a problem for people who have bleeding disorders. Aspirin, warfarin (Coumadin), and other blood-thinning medicines can make bleeding more likely. If you have bleeding or clotting problems, or if you take blood-thinning medicine, tell your doctor before your blood sample is taken.

Blood sample from a heel stick

There is very little chance of a problem from having a heel stick. A small bruise may develop at the site.

There are no risks linked with collecting DNA from saliva, urine, or semen.

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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