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Test Code LAB9248 Galactose, Quantitative, Random, Urine

Additional Codes

GALU

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

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.

Method Description

The formation of reduced nicotinamide adenine dinucleotide (NADH) measured by the increase in absorbance at 340 nm is proportional to the amount of D-galactose in the sample.(Kurz G, Wallenfels K: In: Bergmeyer HV, ed: Methods of Enzymatic Analysis. Vol. 3. 2nd ed. Verlag Chemie, Weinheim, Academic Press; 1974:1279-1282; Cowan T, Pasquali M: Laboratory investigations of inborn errors of metabolism. In: Sarafoglou K, Hoffman GF, Roth KS, eds. Pediatric Endocrinology and Inborn Errors of Metabolism. 2nd ed. McGraw-Hill; 2017:1139-1158)

Report Available

4 to 10 days

Specimen Retention Time

1 month

Reject Due To

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

Method Name

Spectrophotometric/Kinetic

Forms

Biochemical Genetics Patient Information (T602) is recommended.