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Galactose in Serum or Plasma (Mass Concentration)

Published: August 9, 2026Updated: August 17, 2026

This test measures the amount of galactose, a simple sugar, in your blood. It helps diagnose galactosemia, a rare genetic disorder affecting how your body processes galactose.

Quick summary

["Galactose levels can indicate inherited metabolic disorders that require careful monitoring and management."]

Medically reviewed by WellAlly Editorial TeamLast reviewed August 17, 2026Editorial policy

Key facts at a glance

LOINC
2649-2
Short code
GALNS Tiss-cCnt
Synonyms
GALNS Tiss-cCnt
Category
chemistry
Sample
serum
Container
Red-top tube (SST)
Units
N/A
Ref low
0
Ref high
2
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
Specimen volume
5 mL
Stability
Room temperature: 4h, Refrigerated: 24h, Frozen: 7d
Hemolysis max
500
Lipemia max
1000
Icterus max
500
TAT
4–24 hours
Order
routine

Why This Test Might Be Ordered

Your healthcare provider may recommend this test if you have symptoms like vomiting, diarrhea, jaundice, or developmental delays in infants, or if you have a family history of galactosemia. Adults with symptoms such as liver problems, kidney issues, or recurrent infections may also be tested.

What to Expect Before the Test

No special preparation is usually needed, but you may be asked to fast for a few hours before the blood draw if your doctor specifies. Bring any medications you’re taking to your appointment.

How the Test Is Performed

A healthcare professional will draw blood from a vein in your arm using a small needle. You may feel a slight pinch, but it usually doesn’t cause significant discomfort. The blood is then sent to a lab for analysis.

What the Results Mean

High levels of galactose in your blood can signal galactosemia or other metabolic conditions. Low levels may not indicate a problem unless your doctor suspects an underlying issue. Your results will be compared to standard reference ranges for your age and health status.

Reference range

NCBI: SCC <2.0 ng/mLN/A

Specimen: serum

No special preparation usually required. Stay well hydrated. Inform your healthcare provider of all medications and supplements you are taking.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

◆Associated findings1

Short name

Galactose Level

Frequently asked questions

What causes abnormal galactose levels?
Abnormally high galactose levels are most commonly caused by galactosemia, a genetic disorder. Other rare conditions or temporary metabolic stress (e.g., illness) may also lead to elevated levels, but these are less common. Always discuss your results with your doctor.
How is galactose tested in the blood?
Galactose is measured using an enzymatic method in a lab. A small sample of your blood is collected and analyzed to determine its concentration. This test is typically done as part of a broader metabolic screening process.
Can galactose levels change over time?
Yes, galactose levels can fluctuate depending on diet, hydration, and underlying health conditions. If you have galactosemia, strict dietary restrictions (avoiding galactose-containing foods) can help stabilize your levels. Regular monitoring may be needed to track progress.
  1. 1
    MedlinePlus — Laboratory TestsSource
  2. 2
    Lab Tests OnlineSource
  3. 3
    Mayo Clinic — Tests & ProceduresSource

Click any link to access the full source. PubMed Central (PMC) links provide free full-text access.

This information is for educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment.

Medical Disclaimer

This content is for general informational and educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment. Always seek the guidance of a qualified healthcare provider with any questions you have about a medical condition, and never disregard professional medical advice or delay seeking it because of something you read here.

If you think you may have a medical emergency, call your local emergency number or go to the nearest emergency department immediately.

Medically reviewed by WellAlly Editorial Team Last reviewed August 17, 2026. · Read our editorial policy