Ordering Recommendation

Initial test to diagnose or rule out galactosemia.


Enzymatic Assay/Liquid Chromatography-Tandem Mass Spectrometry


Mon, Wed, Fri


2-5 days

New York DOH Approval Status

This test is New York DOH approved.

Specimen Required

Patient Preparation

Green (Sodium or Lithium Heparin), Lavender (K2EDTA), or Pink (K2EDTA). Collect on ice.

Specimen Preparation

DO NOT FREEZE. Transport 7 mL whole blood. (Min: 3 mL)

Storage/Transport Temperature


Unacceptable Conditions

Hemolyzed specimens.


Ambient: Unacceptable; Refrigerated: 5 days; Frozen: Unacceptable

Reference Interval

Greater than or equal to 19.4 U/g Hb

Interpretive Data

One U/g Hb is equivalent to one umol/hour/gram of hemoglobin (umol/hr/g Hb).

This test was developed and its performance characteristics determined by ARUP Laboratories. It has not been cleared or approved by the US Food and Drug Administration. This test was performed in a CLIA certified laboratory and is intended for clinical purposes.

Galactose-1-Phosphate Uridyltransferase activity (umol/hr/g Hb)
Classic galactosemia (G/G) Less than or equal to 0.7
Duarte galactosemia (D/G) 3.1-7.8
Classic galactosemia carrier (G/N) 6.5-16.2
Duarte homozygous (D/D) 6.4-16.5
Duarte carrier (D/N) 12.0-24.0
Normal (N/N) Greater than or equal to 19.4

Compliance Category

Laboratory Developed Test (LDT)


Values for enzyme activity only may not differentiate between variant form of galactosemia or carriers. For a more accurate evaluation of patients suspected to have galactosemia, the preferred test is Galactosemia (GALT) Enzyme Activity and 9 Mutations (ARUP test code 0051175). To monitor therapy in patients with galactosemia, order Galactose-1-Phosphate in Red Blood Cells (ARUP test code 0081296).

Hotline History


CPT Codes



Component Test Code* Component Chart Name LOINC
0080125 Galac-1-Phos Uridyltransferase 24082-0
* Component test codes cannot be used to order tests. The information provided here is not sufficient for interface builds; for a complete test mix, please click the sidebar link to access the Interface Map.


  • Classic Galactosemia
  • Erythrocyte Galactose-1-Phosphate Uridyltransferase Phenotyping
  • Galactosemia
  • GALT
  • GALT Phenotype
Galactose-1-Phosphate Uridyltransferase (GALT Enzyme), RBC