The health professional taking a sample
of your 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
Put the needle into the vein. More than one needle stick
may be needed.
Attach a tube to the needle to fill it with
Remove the band from your arm when enough blood is
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
You start collecting your urine in the
morning. When you first get up, empty your bladder but do not save this urine.
Write down the time that you urinated to mark the beginning of your 24-hour
For the next 24 hours, collect all your urine.
Your doctor or lab will usually provide you with a large container that holds
about 1 gal (4 L). The
container has a small amount of preservative in it. Urinate into a small, clean
container and then pour the urine into the large container. Do not touch the
inside of the container with your fingers.
Keep the large container
in the refrigerator for the 24 hours.
Empty your bladder for the
final time at or just before the end of the 24-hour period. Add this urine to
the large container and record the time.
Do not get toilet paper,
pubic hair, stool (feces), menstrual blood, or other foreign matter in the
The skin sweat test for chloride is primarily used to
test for cystic fibrosis. To learn more, see the topic
How It Feels
The blood sample is taken from a vein
in your arm. An elastic band is wrapped around your upper arm. It may feel
tight. You may feel nothing at all from the needle, or you may feel a quick
sting or pinch.
There is no pain while collecting a
24-hour urine sample.