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Galactosemia Test

Test Overview

Galactose is a sugar that is part of the lactose found in milk and milk products. A galactosemia test is a blood or urine test that checks for enzymes that are needed to change galactose into glucose, a sugar that your body uses for energy. A person with galactosemia doesn't have one of these enzymes, so high levels of galactose build up in the blood or urine.

When galactose builds up in a baby's blood, it can cause liver damage, problems with eating, and intellectual disabilities. The damage caused by galactosemia can begin within weeks after the baby has started drinking breast milk or formula. Babies with galactosemia need foods low in galactose in order to gain weight and to prevent brain damage, liver problems, infection, and cataracts.

Galactosemia is a rare disease that is passed from parents to children (inherited genetic condition). A galactosemia test is usually done to determine whether a newborn has the disease. In a family with a member who has galactosemia, a genetic test can be done on adults to find out whether they have an increased chance of having a child with the disease.

Why It Is Done

A galactosemia test is done to:

  • Find out whether a newborn has the enzymes needed to change galactose into glucose.
  • See whether diet changes are working for a child who has galactosemia.

How To Prepare

You don't need to do anything to prepare for this test.

How It Is Done

Tests for galactosemia are done on a blood or urine sample.

Blood sample from a heel stick

A heel stick is used to get a blood sample from a baby. The baby's heel is poked, and several drops of blood are collected. Your baby may have a tiny bruise where the heel was poked.

Blood sample from a vein

A health professional uses a needle to take a blood sample, usually from the arm.

Urine sample

To test for galactose in a urine sample from a baby, a health professional will tape a plastic collection bag to the baby's genital area. After the baby urinates, the collection bag is removed.

Watch

How It Feels

Blood sample from a heel stick

A quick sting or a pinch is usually felt when the lancet punctures the skin. Your baby may have a little discomfort with the skin puncture, but this doesn't last long.

Blood sample from a vein

Your baby may feel nothing at all from the needle, or he or she may feel a quick sting or pinch.

Urine sample

A baby will usually feel no discomfort from the use of a urine collection bag. But removing the tape that attaches the bag to the skin may cause discomfort for a short time.

Risks

Heel stick blood sample

There is very little risk of a problem from a heel stick. Your baby may get a small bruise at the puncture site.

Blood sample from a vein

There is very little chance of having a problem from this test. A small bruise may form at the site.

Urine sample

There are no risks linked with a urine test for galactosemia. Removing the tape that holds the bag in place may cause mild skin irritation.

Results

The results from a galactosemia test may be negative (galactosemia is not present) or positive (galactosemia is present). Or the results may include specific lab values that mean the person has or does not have galactosemia or is a carrier for it.

A newborn screening test that shows that the baby has an increased risk of galactosemia will be confirmed by other tests.

Many conditions can change galactose levels. Your doctor will discuss any significant abnormal results with you in relation to your baby's symptoms and past health.

Credits

Current as of: July 17, 2020

Author: Healthwise Staff
Medical Review:
Kathleen Romito MD - Family Medicine
Martin J. Gabica MD - Family Medicine
Adam Husney MD - Family Medicine
Siobhan M. Dolan MD, MPH - Reproductive Genetics