Ordering Recommendation

Initial test to diagnose or rule out galactosemia.

Mnemonic
GALT ENZ
Methodology

Enzymatic/Liquid Chromatography-Tandem Mass Spectrometry

Performed

Mon, Wed, Fri

Reported

2-5 days

New York DOH Approval Status
This test is New York DOH approved.
Specimen Required
Patient Preparation
Collect

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

Refrigerated.

Unacceptable Conditions

Hemolyzed specimens.

Remarks
Stability

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).


Genotype
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)

Note

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
N/A
CPT Codes

82775

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