What Is a Blood Test?
A blood test is when a sample of blood
is taken from the body to be tested in a lab. Doctors order blood tests to check things
such as the levels of glucose,
hemoglobin, or white blood cells. This can help them find problems like a disease
or medical condition. Sometimes, blood tests can help them see how well an organ (such
as the liver or kidneys)
is working.
What Is a GGT Test?
A GGT test measures the level of gamma-glutamyl transpeptidase, also called GGT.
GGT is an enzyme found throughout the body, but especially in the liver. A high blood
level of GGT can be a sign of a problem in the liver or bile ducts (which carry bile
from the liver to the intestines to help digest food). If the liver is injured or
irritated or the bile ducts are blocked, the enzyme can leak out of the cells and
cause higher levels in the blood.
Why Are GGT Tests Done?
A GGT test may be done if a child has signs of a possible problem with the liver
or bile ducts, such as jaundice (yellowish skin or eyes), dark urine (pee), light-colored
poop, nausea, vomiting, or belly pain.
It also might be done if a child is on medicine that makes problems with the liver
or bile ducts more likely, or if the results of another liver enzyme test were abnormal.
How Should We Prepare for a GGT Test?
Your child may be asked to stop eating and drinking for 8 to 12 hours before the
GGT test. Tell your doctor about any medicines your child takes because some drugs
might affect the test results.
Wearing a T-shirt or short-sleeved shirt for the test can make things easier for
your child, and you also can bring along a toy or book as a distraction.
How Is a GGT Test Done?
Most blood tests take a small amount of blood from a vein. To do that, a health
professional will:
- clean the skin
- put an elastic band (tourniquet) above the area to get the veins to swell with
blood
- insert a needle into a vein (usually in the arm inside of the elbow or on the
back of the hand)
- pull the blood sample into a vial or syringe
- take off the elastic band and remove the needle from the vein
In babies, blood draws are sometimes done as a "heel stick collection." After cleaning
the area, the health professional will prick your baby's heel with a tiny needle (or
lancet) to collect a small sample of blood.
Collecting a sample of blood is only temporarily uncomfortable and can feel like
a quick pinprick.
