Test ID G6SW N-Acetylgalactosamine-6-Sulfatase, Leukocytes
Useful For
Preferred test to rule-out mucopolysaccharidosis IVA (Morquio A syndrome)
The test is not useful for establishing carrier status for Morquio A syndrome.
Genetics Test Information
This is the preferred test to rule-out mucopolysaccharidosis IVA, (MPS IVA; Morquio A syndrome).
Morquio A is an autosomal recessive mucopolysaccharidosis caused by reduced or absent N-acetylgalactosamine-6-sulfate sulfatase enzyme activity.
Although clinically similar, Morquio A is distinct from Morquio B at the molecular and enzyme levels. Enzyme analysis is necessary to distinguish between the two.
Special Instructions
Method Name
Fluorometric
Reporting Name
N-Acetylgalactosamine 6 Slft, WBCSpecimen Type
Whole Blood ACDOrdering Guidance
This test cannot be used to establish carrier status for Morquio A syndrome; sequencing of the GALNS gene is recommended. Order CGPH / Custom Gene Panel, Hereditary, Next-Generation Sequencing, Varies and specify Gene List ID: EMCP-JUFPRX.
Shipping Instructions
For optimal isolation of leukocytes, it is recommended the specimen arrive within 7 days of collection to be stabilized. Collect specimen Monday through Thursday only and not the day before a holiday. Specimen should be collected and packaged as close to shipping time as possible.
Specimen Required
Container/Tube:
Preferred: Yellow top (ACD solution B)
Acceptable: Yellow top (ACD solution A)
Specimen Volume: 6 mL
Collection Instructions: Send whole blood specimen in original tube. Do not aliquot.
Specimen Minimum Volume
5 mL
Specimen Stability Information
Specimen Type | Temperature | Time | Special Container |
---|---|---|---|
Whole Blood ACD | Refrigerated (preferred) | 7 days | YELLOW TOP/ACD |
Ambient | 7 days | YELLOW TOP/ACD |
Reference Values
≥92 nmol/17 hour/mg protein
Day(s) Performed
Preanalytical processing: Monday through Saturday
Assay performed: Once per month
Performing Laboratory

CPT Code Information
82657
LOINC Code Information
Test ID | Test Order Name | Order LOINC Value |
---|---|---|
G6SW | N-Acetylgalactosamine 6 Slft, WBC | 24096-0 |
Result ID | Test Result Name | Result LOINC Value |
---|---|---|
62409 | N-Acetylgalactosamine 6 Slft, WBC | 24096-0 |
35778 | Interpretation (G6SW) | 59462-2 |
35777 | Reviewed By | 18771-6 |
Test Classification
This test was developed, and its performance characteristics determined by Mayo Clinic in a manner consistent with CLIA requirements. This test has not been cleared or approved by the US Food and Drug Administration.Report Available
30 to 45 daysNY State Approved
YesForms
1. New York Clients-Informed consent is required. Document on the request form or electronic order that a copy is on file. The following documents are available:
-Informed Consent for Genetic Testing (T576)
-Informed Consent for Genetic Testing-Spanish (T826)
2. Biochemical Genetics Patient Information (T602)
3. If not ordering electronically, complete, print, and send a Biochemical Genetics Test Request (T798) with the specimen.
Testing Algorithm
For information see Lysosomal Storage Disorders Diagnostic Algorithm, Part 1