Test Code GALU Galactose, Quantitative, Urine
Reporting Name
Galactose, QN, UUseful For
Screening test for galactosemia using urine specimens
Testing Algorithm
See Galactosemia Testing Algorithm in Special Instructions.
Performing Laboratory

Specimen Type
UrineAdvisory Information
This test is not recommended for follow-up of positive newborn screening results. or for diagnosis of galactosemia. The preferred test to evaluate for possible diagnosis of galactosemia, routine carrier screening, and followup of abnormal newborn screening results is GCT / Galactosemia Reflex, Blood along with GAL1P / Galactose-1-Phosphate, Erythrocytes.
This test is not appropriate for monitoring of galactosemia. For monitoring, order GAL1P / Galactose-1-Phosphate , Erythrocytes.
Necessary Information
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
Supplies: Aliquot Tube, 5 mL (T465)
Collection Container/Tube: Clean, plastic urine collection container
Submission Container/Tube: Plastic, 5-mL tube
Specimen Volume: 1 mL
Collection Instructions: Collect a random urine specimen.
Specimen Minimum Volume
0.5 mL
Specimen Stability Information
Specimen Type | Temperature | Time | Special Container |
---|---|---|---|
Urine | Frozen (preferred) | 365 days | |
Ambient | 20 days | ||
Refrigerated | 20 days |
Special Instructions
Reference Values
<30 mg/dL
Day(s) and Time(s) Performed
Tuesday; a.m.
Test Classification
This test was developed and its performance characteristics determined by Mayo Clinic in a manner consistent with CLIA requirements. This test has not been cleared or approved by the U.S. Food and Drug Administration.CPT Code Information
82760
LOINC Code Information
Test ID | Test Order Name | Order LOINC Value |
---|---|---|
GALU | Galactose, QN, U | 2310-1 |
Result ID | Test Result Name | Result LOINC Value |
---|---|---|
8765 | Galactose, QN, U | 2310-1 |
Clinical Information
Galactosemia is an autosomal recessive disorder that results from a deficiency of any 1 of the 3 enzymes catalyzing the conversion of galactose to glucose: galactose-1-phosphate uridyltransferase (GALT), galactokinase (GALK), and uridine diphosphate galactose-4-epimerase (GALE). GALT deficiency is the most common cause of galactosemia and is often referred to as classic galactosemia. The complete or near-complete deficiency of GALT enzyme is life-threatening if left untreated. Complications in the neonatal period include failure to thrive, liver failure, sepsis, and death.
Galactosemia is treated by a galactose-restricted diet, which allows for rapid recovery from the acute symptoms and a generally good prognosis. Despite adequate treatment from an early age, individuals with galactosemia remain at increased risk for developmental delays, speech problems, and abnormalities of motor function. Females with galactosemia are at increased risk for premature ovarian failure. Based upon reports by newborn screening programs, the frequency of classic galactosemia in the United States is approximately 1 in 30,000, although literature reports range from 1 in 10,000 to 1 in 60,000 live births.
A comparison of plasma and urine galactose and blood galactose-1-phosphate (Gal-1-P) levels may be useful in distinguishing among the 3 forms of galactosemia; however, these are only general patterns and further confirmatory testing would be required to make a diagnosis.
Deficiency |
Galactose (Plasma/Urine) |
Gal-1-P (Blood) |
GALK |
Elevated |
Normal |
GALT |
Elevated |
Elevated |
GALE |
Normal-Elevated |
Elevated |
See Galactosemia Testing Algorithm in Special Instructions for additional information.
Analytic Time
8 daysReject Due To
All specimens will be evaluated at Mayo Clinic Laboratories for test suitability. |
NY State Approved
YesMethod Name
Spectrophotometric, Kinetic
Forms
1. Biochemical Genetics Patient Information (T602) is recommendation, see Special Instructions.
2. If not ordering electronically, complete, print, and send an Inborn Errors of Metabolism Test Request (T798) with the specimen.