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 three 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 brain damage, seizures, 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 disorder). 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 determine whether they have an increased chance of having a child with the disease.