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Test Code LAB995 Galactose 1 Phosphate, Metabolite Quantification

Important Note

Test requires special processing.  Call Biochemical Genetics (987-2216) or Chemistry (987-2565) when collected. Testing must be collected during dayshift hours 7am – 3pm, Monday – Friday.  

Weekend collections can be done with coordination from the Chemistry team (987-2565) in advance.

SCH Laboratory is permitted to draw blood on adults for this test.

Clinical System Name

Galactose 1 Phosphate, Metabolite Quantification

Synonyms

G1P; Gal-1-P; GAL1P;

Sample Requirements

Specimen: Whole Blood

Container(s):  Dark Green/Sodium Heparin Tube, Yellow/ACD A or B, Lavender/EDTA

Preferred Vol: 2.0 mL

Minimum Vol: 1.0 mL

 

Note:  Do NOT use gel separator tubes.

Processing Instructions

Reject due to: 

Spin: N

Aliquot:N

Temp: RT

Special instructions:  Notify Biochemical Genetics (987-2216)  immediately so that cells can be washed before storing at -70 C. If not available, follow "Weekend Processing" instructions below. Blood collection on adults is permitted.

Weekend Processing: Call Chemistry West (987-2565). Procedure can be found in RBC enzyme section.

 

Off-site collection: Special processing required. Call biochemical genetics prior to collection with questions about processing. Samples received from outside labs should be frozen washed cells.  Store cells at -70 C (although -20 C is acceptable for short term transport). Cells must not thaw during transport.

Stability

Specimen Type Temperature Time
whole blood Room temp

≤1 h after collection
whole blood Refrigerated < 1 h after collection
washed, frozen red cells > -20C  stable if cells remain frozen on transport

 

Availability

STAT Performed TAT
N Weekly 7 d

 

Contact the Biochemical Genetics Lab for requests outside of stated availability (206)987-2216.

Performing Laboratory

Seattle Children's Laboratory    

Department

Department:  Biochemical Genetics

Phone Number: 206-987-2216

 

CPT Codes

84378

Methodology

Method: Fluorometric

Analytical Volume:

Limitations:

Reference Range

  Range

Preferred range for patients with galactosemia

 < 4 mg/dL
Normal range for patients without galactosemia <1 mg/dL

 

Description

Used to monitor treatment of known Galactosemia patients.

Clinical Utility

Galactosemia is an inherited disorder of galactose metabolism. Individuals with galactosemia are unable to break down galactose, a sugar found primarily in dairy products and some vegetables and legumes. Galactosemia is caused by a deficiency in the enzyme galactose-1-phosphate uridyltransferase, and individuals with galactosemia have mutations in the GALT gene. They also have elevated galactose-1-phosphate, a metabolite of galactose metabolism that is used for dietary monitoring in affected patients. Patients with defects in the GALE gene (UDP-galactose-4-epimerase deficiency) would also have elevated galactose-1-phosphate. patients with defects in the GALK  gene (galactokinase deficiency) would have normal galactose 1-phosphate, but elevated galactose.

Requisition

Biochemical Genetics Requisition

 

On the requisition include clinical information needed for appropriate interpretation. (Age, gender, drug therapy and family history)