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.
Note: All information is for educational purposes only. For specific medical advice, diagnoses, and treatment, consult your doctor.
