Test Code GALT Galactose-1-Phosphate Uridyltransferase, Blood
Ordering Guidance
This assay is not appropriate for monitoring dietary compliance. If dietary monitoring is needed, order GAL1P / Galactose-1-Phosphate, Erythrocytes.
This test is for galactose-1-phosphate uridyltransferase (GALT) enzyme testing only. The preferred test to evaluate for possible diagnosis of galactosemia, routine carrier screening, and follow-up of abnormal newborn screening results is GCT / Galactosemia Reflex, Blood.
This assay will not detect galactokinase (GALK) deficiency or uridine diphosphate-galactose 4' epimerase (GALE) deficiency.
-To evaluate for GALK deficiency, order GALK / Galactokinase, Blood.
-To evaluate for GALE deficiency, order GALE / Uridine Diphosphate -Galactose 4' Epimerase, Blood.
-To evaluate for GALM deficiency, order GALP / Galactose, Plasma and molecular analysis of the GALM gene.
Necessary Information
Patient's age is required.
Biochemical Genetics Patient Information (T602) is recommended, but not required, to be filled out and sent with the specimen to aid in the interpretation of test results.
Specimen Required
Multiple whole blood tests for galactosemia can be performed on 1 specimen. Prioritize order of testing when submitting specimens. For a list of tests that can be ordered together see Galactosemia-Related Test List.
Container/Tube:
Preferred: Lavender top (EDTA)
Acceptable: Green top (sodium heparin) or yellow top (ACD)
Specimen Volume: 5 mL
CMH COLLECTION: 3 mL in EDTA lavender vacutainer
Specimen Minimum Volume
2 mL
Specimen Stability Information
Specimen Type | Temperature | Time | Special Container |
---|---|---|---|
Whole Blood EDTA | Refrigerated (preferred) | 28 days | |
Ambient | 14 days |
Testing Algorithm
For more information see Galactosemia Testing Algorithm.
Useful For
Diagnosis of galactose-1-phosphate uridyltransferase deficiency, the most common cause of galactosemia
Confirmation of abnormal state newborn screening results
Reject Due To
Gross hemolysis | Reject |
Day(s) Performed
Monday, Wednesday, Friday
Report Available
4 to 7 daysReporting Name
Gal-1-P Uridyltransferase, RBCReference Values
≥24.5 nmol/h/mg of hemoglobin
Method Name
Enzyme Reaction followed by Liquid Chromatography Tandem Mass Spectrometry (LC-MS/MS)
Performing Laboratory
Mayo Clinic Laboratories in RochesterCPT Code Information
82775