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.
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.