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Test Code GALU Galactose, Quantitative, Urine

Reporting Name

Galactose, QN, U

Useful For

Screening test for galactosemia using urine specimens

Testing Algorithm

See Galactosemia Testing Algorithm in Special Instructions.

Performing Laboratory

Mayo Clinic Laboratories in Rochester

Specimen Type

Urine


Advisory 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

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 days

Reject Due To

All specimens will be evaluated at Mayo Clinic Laboratories for test suitability.

NY State Approved

Yes

Method 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.