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HelpTest Code MUGS Hexosaminidase A, Serum
Performing Laboratory
Mayo Clinic Laboratories in Rochester
Reporting Name
Hexosaminidase A (MUGS), SSpecimen Type
SerumOrdering Guidance
Testing for Tay-Sachs Disease and Sandhoff Disease
The following tests are available for diagnostic and carrier testing for Tay-Sachs and Sandhoff diseases.
NAGR / Hexosaminidase A and Total, Leukocytes/Molecular Reflex, Whole Blood:
-This is the recommended test for carrier testing for Tay-Sachs disease and Sandhoff disease.
-Testing begins with hexosaminidase A and total enzyme analysis. If the results are consistent with an affected or carrier for Tay-Sachs disease or Sandhoff disease, next-generation sequencing to detect single nucleotide and copy number variants for HEXA or HEXB, respectively, will automatically be performed on the original specimen.
-This test is appropriate for males and pregnant or nonpregnant females.
NAGW / Hexosaminidase A and Total Hexosaminidase, Leukocytes:
-This test can be used for diagnosis and carrier testing for Tay-Sachs disease or Sandhoff disease.
-Results for hexosaminidase A and total enzyme analysis are reported with recommendations for additional testing when appropriate. All follow-up testing must be ordered separately on new specimens.
-This test is appropriate for males and pregnant or nonpregnant females.
NAGS / Hexosaminidase A and Total Hexosaminidase, Serum:
-This test can be used for diagnosis and carrier testing for Tay-Sachs disease or Sandhoff disease. Results for hexosaminidase A and total enzyme analysis are reported with recommendations for additional testing when appropriate.
-If results indicate normal, indeterminate, or carrier status and the suspicion of Tay-Sachs disease remains high, MUGS / Hexosaminidase A, Serum for Tay-Sachs disease (B1 variant) can typically be added and performed on the same specimen.
-With the exception of MUGS, all follow-up testing must be ordered separately on new specimens.
-This test is not appropriate for pregnant females or women receiving hormonal contraception. This test is appropriate for males and nonpregnant females.
-This test is particularly useful when it is difficult to obtain enough blood to perform leukocyte testing (NAGR or NAGW), as may be the case with infants.
MUGS / Hexosaminidase A, Serum:
-This is the recommended test for diagnosis and carrier testing for the B1 variant of Tay-Sachs disease. This test will not detect Sandhoff disease.
-This test should not be ordered as a first-line test. Rather, this test should be ordered when the NAGR, NAGW, or NAGS indicate normal, indeterminate, or carrier results and the suspicion of Tay-Sachs disease remains high. In most cases, this test can be performed on the original specimen collected for NAGS.
Necessary Information
Healthcare professional name and phone number are required.
Specimen Required
Patient Preparation: Patient should be fasting for 4 hours.
Supplies: Sarstedt Aliquot Tube, 5 mL (T914)
Collection Container/Tube:
Preferred: Serum gel
Acceptable: Red top
Submission Container/Tube: Plastic vial
Specimen Volume: 1 mL
Collection Instructions: Centrifuge and aliquot serum into plastic vial.
Reject Due To
| Gross hemolysis | OK |
| Gross lipemia | OK |
Specimen Stability Information
| Specimen Type | Temperature | Time | Special Container |
|---|---|---|---|
| Serum | Frozen (preferred) | 365 days | |
| Refrigerated | 5 days |
Specimen Minimum Volume
0.15 mL
Special Instructions
Day(s) Performed
Once per month
Specimen Retention Time
30 daysReport Available
2 to 8 daysReference Values
1.23-2.59 U/L (Normal)
1.16-1.22 U/L (Indeterminate)
0.58-1.15 U/L (Carrier)
Useful For
Second-order test for diagnosing the B1 variant of Tay-Sachs disease
This test is not useful for testing for Sandhoff disease.
Testing Algorithm
For more information see Tay-Sachs and Related Disorders Diagnostic Testing Algorithm
CPT Code Information
83080
LOINC Code Information
| Test ID | Test Order Name | Order LOINC Value |
|---|---|---|
| MUGS | Hexosaminidase A (MUGS), S | 2643-5 |
| Result ID | Test Result Name | Result LOINC Value |
|---|---|---|
| 80350 | Hexosaminidase A (MUGS), S | 2643-5 |
Supportive Data
Regression analysis shows a linear relationship between Mayo Clinic Laboratories' MUG and 4-MUGS methods (R=0.964). A normal range of 1.23 to 2.59 U/L hexosaminidase A was determined using the 4-methylumbelliferyl-beta-D-N-acetyl-glucosamine-6-sulfate (4-MUGS) procedure on 50 normal subjects. A Tay-Sachs carrier range, based on results from 12 obligate carriers for Tay-Sachs disease, has been established tentatively as 0.58 to 1.15 U/L. This range will continue to be evaluated as more obligate carriers for Tay-Sachs disease are studied.
Forms
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.