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Test Code GALU Galactose, Quantitative, Random, Urine

Reporting Name

Galactose, QN, U

Useful For

Screening test for galactosemia using urine specimens

Testing Algorithm

For information, see Galactosemia Testing Algorithm.

Performing Laboratory

Mayo Clinic Laboratories in Rochester

Specimen Type

Urine


Ordering Guidance


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 follow-up 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: Sarstedt Aliquot Tube, 5 mL (T914)

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

Reference Values

<30 mg/dL

Day(s) Performed

Tuesday

Test Classification

This test was developed and its performance characteristics determined by Mayo Clinic in a manner consistent with CLIA requirements. It has not been cleared or approved by the US 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

Interpretation

Additional testing is required to investigate the cause of abnormal results.

 

In patients with galactosemia, elevated galactose in plasma or urine may suggest ineffective dietary restriction or compliance; however, the concentration of galactose-1-phosphate in erythrocytes (GAL1P / Galactose-1-Phosphate, Erythrocytes) is the most sensitive index of dietary control for patients with galactose-1-phosphate uridyltransferase and uridine diphosphate galactose-4-epimerase deficiencies.

 

Increased concentrations of galactose may also be suggestive of severe hepatitis, biliary atresia of the newborn, and, in rare cases, galactose intolerance.

 

If galactosemia is suspected, additional testing to identify the specific enzymatic defect is required. See Galactosemia Testing Algorithm for follow-up of abnormal newborn screening results, comprehensive diagnostic testing, and carrier testing. Results should be correlated with clinical presentation and confirmed by specific enzyme or molecular analysis. For more information see Ordering Guidance.

Clinical Reference

1. Berry GT: Classic galactosemia and clinical variant galactosemia. In: Adam MP, Everman DB, Mirzaa GM, et al. eds. GeneReviews [Internet]. University of Washington, Seattle; 2000. Updated March 11, 2021. Accessed September 10, 2024. Available at www.ncbi.nlm.nih.gov/books/NBK1518/

2. Walter JH, Fridovich-Keil JL: Galactosemia. In: Valle D, Antonarakis S, Ballabio A, Beaudet AL, Mitchell GA, eds. The Online Metabolic and Molecular Bases of Inherited Disease. McGraw-Hill; 2019. Accessed September 10, 2024. Available at https://ommbid.mhmedical.com/content.aspx?bookid=2709&sectionid=%20225081023

3. Yazici H, Canda E, Altinok YA, Ucar SK, Coker M. Two siblings with galactose mutarotase deficiency: Clinical differences. JIMD Rep. 2021;63(1):25-28. doi:10.1002/jmd2.12263

Report Available

4 to 10 days

Method Name

Spectrophotometric/Kinetic

Forms

Biochemical Genetics Patient Information (T602) is recommended.