Beta-Galactosidase, Dried Blood Spot (Referred Out) - Saskatoon
Discipline
Biochemistry
Overview
Description
- This test is a quantitative enzyme activity, and the enzyme activity is measured using dried blood spots.
Test Ordering Requirements
Forms Required
- Requisitions must have specific test indicated
- Miscellaneous Specimen Requisition Form #101878 or SHR Laboratory Medicine Community Laboratory Requisition Form #101064 or Acute Care Phlebotomy Requisition Form #101062
Alias
- MPS IVB
- Morquio Syndrome
- GM1 Gangliosidosis
Specimen Information
Specimen types accepted
- Whole Blood
Specimen collection container
- Preferred Collection Container: Dark Green (Lithium Heparin) 4.0mL
- Alternate Collection Container: Dark Green (Sodium Heparin) 4.0mL
- Alternate Collection Container: Lavender (EDTA) 4.0mL
Required volume
- Optimal Volume: 4 mL whole blood
- Minimum/Pediatric Volume: 1 mL whole blood
Transport and stability
- Whole blood must be received within 24 hours of collection
- Store whole blood at room temperature
- Neonatal Screen Card should be spotted with whole blood within 24 hours of collection.
- Once spotted, the Neonatal Screen Card should be allowed to dry for 3-4 hours & shipped to referral laboratory at ambient temperature.
Rejection criteria
- Specimens received where the proper collection protocols were not followed
- Pathology and Laboratory Medicine Acceptance and Rejection Criteria
Testing Information
Relevant clinical history
- Family history
- Must include diagnosis and/or patient symptoms on the requisition.
Clinical interpretation
- Results should be interpreted in the context of patient history, clinical findings and other laboratory data.
Performance
Methodology
- Quantifies level of beta-galactosidase via the 4-methylumbelliferyl substrate
Days/times performed
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Maximum laboratory time
- 2 week turnaround time by referral laboratory
Other information
Additional Comments
- The Neonatal Screen card will be spotted when whole blood received in the lab.
- This test is useful to distinguish between Mucopolysaccharidosis (MPS) type IV A and B. MPS IV is also known as Morquio Syndrome.
- MPS IVB is caused by deficiency of the enzyme beta-galactosidase encoded by the GLB1 gene location on chromosome 3p21.33; MPS IVA is caused by mutations in the GALNS gene on chromosome 16q24 that encodes the enzyme N-acetylgalactosamine-6-sulfatase (responsible for degradation of keratin sulfate and chondroitin-6-sulfate).
- Patients with MPS IVB have decreased affinity and catalytic activity of the enzyme for keratin sulfate with preservation of degradative activity for GM1 ganglioside
Last Updated: October 4, 2024