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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.

Method Name


Reporting Name

N-Acetylgalactosamine 6 Slft, WBC

Specimen Type

Whole Blood ACD

Ordering 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


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

Mayo Clinic Laboratories in Rochester

CPT Code Information


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 days

NY State Approved



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