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Test ID GALK Galactokinase, Blood

Useful For

Diagnosis of galactokinase deficiency, the second most common cause of galactosemia

Highlights

Galactokinase (GALK) deficiency is a milder form of galactosemia that results in cataracts, which are preventable with a lactose-restricted diet.

 

Deficient GALK enzyme activity in erythrocytes is diagnostic for galactokinase deficiency.

 

In GALK deficiency, erythrocyte galactose-1-phosphate levels are normal, whereas plasma galactose levels are elevated.

 

The results of testing performed in erythrocytes are invalid following a transfusion, including analysis of enzymes, biochemical phenotyping, or galactose-1-phosphate.

Method Name

Enzyme Reaction Followed by Liquid Chromatography-Tandem Mass Spectrometry (LC-MS/MS)

Reporting Name

Galactokinase, B

Specimen Type

Whole Blood EDTA

Specimen Required

Container/Tube:

Preferred: Lavender top (EDTA)

Acceptable: Green top (sodium heparin), green top (lithium heparin), or yellow top (ACD)

Specimen Volume: 4 mL

Forms: New York Clients-Informed consent is required. Please document on the request form or electronic order that a copy is on file. An Informed Consent for Genetic Testing (Supply T576) is available in Special Instructions.

Specimen Minimum Volume

2 mL

Specimen Stability Information

Specimen Type Temperature Time
Whole Blood EDTA Refrigerated (preferred) 10 days
  Ambient  72 hours

Reference Values

≥0.7 nmol/h/mg of hemoglobin

Day(s) and Time(s) Performed

Mondays; 9 a.m.

Performing Laboratory

Mayo Medical Laboratories in Rochester

CPT Code Information

82759

LOINC Code Information

Test ID Test Order Name Order LOINC Value
GALK Galactokinase, B 81143-0

 

Result ID Test Result Name Result LOINC Value
38005 Galactokinase, B In Process
38007 Interpretation (GALK) In Process
38006 Reviewed By No LOINC Needed

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.

Testing Algorithm

See Galactosemia Testing Algorithm in Special Instructions.