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Test Code GATOL Galactitol, Quantitative, Urine

Performing Laboratory

Mayo Clinic Laboratories in Rochester

Reporting Name

Galactitol, QN, U

Specimen Type

Urine


Ordering Guidance


To monitor dietary ingestion of galactose, order GAL1P / Galactose-1-Phosphate, Erythrocytes.



Necessary Information


Patient's age is required.



Specimen Required


Supplies: Urine Tubes, 10 mL (T068)

Container/Tube: Plastic, 10-mL urine tube

Specimen Volume: 2 mL

Collection Instructions:

1. Collect a random urine specimen.

2. No preservative.


Reject Due To

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

Specimen Stability Information

Specimen Type Temperature Time
Urine Refrigerated (preferred) 28 days
  Frozen  28 days

Specimen Minimum Volume

1 mL

Day(s) Performed

Tuesday, Friday

Specimen Retention Time

3 months

Report Available

3 to 7 days

Reference Values

0-11 months: <109 mmol/mol creatinine

1-3 years: <52 mmol/mol creatinine

4-17 years: <16 mmol/mol creatinine

≥18 years: <13 mmol/mol creatinine

Useful For

Monitoring effectiveness of treatment in patients with galactosemia

 

Establishing a baseline level prior to initiating treatment for galactosemia

CPT Code Information

82542

LOINC Code Information

Test ID Test Order Name Order LOINC Value
GATOL Galactitol, QN, U 47857-8

 

Result ID Test Result Name Result LOINC Value
35831 Galactitol 47857-8
35832 Interpretation (GATOL) 59462-2
35833 Reviewed By 18771-6

Method Description

A total of 200 mcL of urine are spiked with a mixture of labeled internal standards, allowed to equilibrate, and evaporated. The dry residue is derivatized to form trimethylsilyl  esters, then extracted with hexane. Specimens are analyzed by gas chromatography mass spectrometry, selected ion monitoring using ammonia chemical ionization and a stable isotope dilution method.(Jansen G, Muskiet F, Schierbeek H, et al. Capillary gas chromatography profiling of urinary, plasma, and erythrocyte sugars and polyols as their trimethylsilyl derivatives, preceded by a simple and rapid prepurification method. Clin Chim Acta. 1986;157:277-294; Marolt G, Kolar M. Analytical Methods for Determination of Phytic Acid and Other Inositol Phosphates: A Review. Molecules. 2020;26[1]:174)

Disease States

  • Galactosemia

Genetics Test Information

This test may be used as an aid in the diagnosis of galactosemia.

 

Urinary galactitol is often not affected by acute dietary ingestion of galactose; therefore, it is not a substitute for galactose-1-phosphate in monitoring diet.