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Test Code Morquio A Galactose-6-sulfatase

Clinical System Name

galactose-6-sulfatase

Synonyms

Morquio enzyme

Morquio A

MPS IVa

Morquio B

Beta-galactosidase

Description

Fluorometric enzyme test for N-galactose-6-sulfatase for diagnosis of Morquio A (MPS IV a).  Beta-galactosidase is included in the test as a control, and can be used for the diagnosis of Morquio B (MPS IV b).

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.

 

Processing Instructions

Reject due to:

Spin: N

Aliquot:N

Temp:RT

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 M-Th at room temperature via overnight shipping.

Stability

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.

Availability

STAT Performed TAT
N Weekly 7-10 days

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

 

 

Reference Range

 

Specimen Type Normal Range (nmol/17hr/mg protein)

WBC

25-200
FB (Fibroblast) 95-360

 

Methodology

Method: 4 Mu Fluorometric assay

Analytical Volume:

Limitations:

CPT Codes

82657

Requisition

Biochemical Genetics Requisition

 

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

Clinical Utility

Enzyme testing for Morquio would be indicated in a child with skeletal findings suggestive of Morquio disease with or without an elevated urine mucopolysaccharide (MPS). Urine MPS is typically elevated in all individuals with MPS disorders, including MPS IV, however, the sensitivity of the MPS assay for keratan sulfate (excreted in MPS IV), is lower than for other glycosaminoglycans.

 

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