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Galactosemia Test


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 a problem from having blood drawn from a vein.

  • Your baby may get a small bruise at the puncture site. You can lower the chance of bruising by keeping pressure on the site for several minutes.
  • In rare cases, the vein may become swollen after the blood sample is taken. This problem is called phlebitis. You can use a warm compress several times a day to treat this.

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.


A galactosemia test is a blood or urine test that checks for the enzymes that are needed to change galactose into glucose, a sugar that your body uses for energy.

Galactose tests (blood or urine)

Negative (galactosemia is not present)


Positive (galactosemia is present)

The normal values listed here-called a reference range-are just a guide. These ranges vary from lab to lab, and your lab may have a different range for what's normal. Your lab report should contain the range your lab uses. Also, your doctor will evaluate your results based on your health and other factors. This means that a value that falls outside the normal values listed here may still be normal for you or your lab.

Galactose-1-phosphate uridyltransferase (GPT) test (blood)

18.5-28.5 units per gram (U/g) of hemoglobin (1.19-1.84 milliunits per mole of hemoglobin [mU/mol Hb]): The person does not have galactosemia.


Less than 5 U/g of hemoglobin (less than 0.32 mU/mol Hb): The person has galactosemia.

5-18.5 U/g of hemoglobin (0.32-1.18 mU/mol Hb): The person may be a carrier of galactosemia and able to pass the disease on to his or her child.

WebMD Medical Reference from Healthwise

Last Updated: August 07, 2014
This information is not intended to replace the advice of a doctor. Healthwise disclaims any liability for the decisions you make based on this information.

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