Get answers to your child's growth, nutrition, and feeding
behavior questions. Beta-carotene is the precursor to vitamin A.
A test can be done to measures the amount of beta-carotene in
blood. See also: Vitamin A test Blood is drawn from a vein,
usually from the inside of the elbow or the back of the hand.
The site is cleaned with germ-killing medicine (antiseptic). The
health care provider wraps an elastic band around the upper arm
to apply pressure to the area and make the vein swell with
blood. Next, the health care provider gently inserts a needle
into the vein. The blood collects into an airtight vial or tube
attached to the needle. The elastic band is removed from your
arm. Once the blood has been collected, the needle is removed,
and the puncture site is covered to stop any bleeding. In
infants or young children, a sharp tool called a lancet may be
used to puncture the skin and make it bleed. The blood collects
into a small glass tube called a pipette, or onto a slide or
test strip. A bandage may be pl