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Test Code GALP Galactose, Quantitative, Plasma

Reporting Name

Galactose, QN, P

Performing Laboratory

Mayo Clinic Laboratories in Rochester

Useful For

Screening for galactosemia

Method Name

Spectrophotometric/Kinetic


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.

 

The preferred test for monitoring dietary therapy is GAL1P / Galactose-1-Phosphate, Erythrocytes for both GALT and GALE deficiencies.

 

This test may be useful for monitoring in patients with GALM deficiency.



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


Collection Container/Tube: Green top (sodium heparin)

Submission Container/Tube: Plastic vial

Specimen Volume: 0.5 mL

Collection Instructions: Centrifuge and aliquot plasma into a plastic vial


Specimen Type

Plasma Na Heparin

Specimen Minimum Volume

0.2 mL

Specimen Stability Information

Specimen Type Temperature Time Special Container
Plasma Na Heparin Frozen (preferred) 365 days
  Ambient  20 days
  Refrigerated  20 days

Reject Due To

Gross hemolysis OK
Gross lipemia OK

Reference Values

≤7 days: <5.4 mg/dL

8-14 days: <3.6 mg/dL

≥15 days: <2.0 mg/dL

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

Day(s) Performed

Tuesday

Report Available

4 to 10 days

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
GALP Galactose, QN, P 2308-5

 

Result ID Test Result Name Result LOINC Value
83638 Galactose, QN, P 2308-5

Forms

1. Biochemical Genetics Patient Information (T602) is recommended.

2. If not ordering electronically, complete, print, and send a Biochemical Genetics Test Request (T798) with the specimen.

Testing Algorithm

For more information see Galactosemia Testing Algorithm.