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Test Code B Gal GM1 Beta Galactosidase

Clinical System Name

Beta Galactosidase


B Gal GM1

GM1 Gangliosidosis

Beta Gal


Fluorometric enzyme test for beta galactosidase for diagnosis of GM 1 gangliosidosis.

Sample Requirements

Specimen: Whole Blood

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

Preferred Vol:10.0 mL

Minimum Vol: 6.0 mL


Note: Also acceptable:  cultured cells from skin fibroblasts (2 confluent T-25 flasks)

Do NOT use gel separator tubes.



Specimen Type Temperature Time
  Room temp

≤24 hrs

  Refrigerated < 24 hrs

Samples received > 24 hr after blood collection will still be processsed and test performed if possible.


STAT Performed TAT
N Weekly 7-10 days

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

Processing Instructions

Reject due to:

Spin: N



Storage location: Biochemical Genetics Box- RT

Weekend Processing: Contact Chem West (x72565) on dayshift. If Chemistry team is unavailable, sample should be stored in RT Biochemical Genetics box.


Off-site collection: Do not spin!  Keep at room temperature.  Transport Mon-Thurs at room temperature via overnight shipping.

Clinical Utility

Deficiency of beta-galactosidase is supportive of a diagnosis of GM1 gangliosidosis. GM1 gangliosidosis may present as early infantile, late infantile, and adult onset.
Infantile forms present with symptoms including seizures, hepatosplenomegaly, coarse facial features, skeletal irregularities, joint stiffness, muscle weakness and exaggerated startle response to sound. Cherry-red spots in the eyes are common. Adult onset disease may present with muscle atrophy, corneal clouding,dystonia, and without hepatosplenomegaly.


This test is not appropriate for determining carrier status or for prenatal diagnosis.


Performing Laboratory

Seattle Children's Laboratory    


Department:  Biochemical Genetics

Phone Number: 206-987-2216




Method: 4 Mu Fluorometric assay

Analytical Volume:



Biochemical Genetics Requisition


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

Reference Range


Specimen Type Normal Range (nmol/hr/mg protein)


FB (Fibroblast) 150-475


CPT Codes