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Test ID NAGS Hexosaminidase A and Total Hexosaminidase, Serum

Useful For

Carrier detection and diagnosis of Tay-Sachs disease and Sandhoff disease

 

This test is not useful for pregnant females or those treated with hormonal contraception.

Method Name

Heat Inactivation, Fluorometric, Automated

Reporting Name

Hexosaminidase A and Total, S

Specimen Type

Serum


Ordering 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):

-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, 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.



Specimen Required


Container/Tube:

Preferred: Red top

Acceptable: Serum gel

Specimen Volume: 1 mL


Specimen Minimum Volume

0.5 mL

Specimen Stability Information

Specimen Type Temperature Time Special Container
Serum Frozen (preferred) 30 days
  Refrigerated  7 days

Reference Values

HEXOSAMINIDASE TOTAL

≤15 years: ≥20 nmol/min/mL

≥16 years: 10.4-23.8 nmol/min/mL

 

HEXOSAMINIDASE PERCENT A

≤15 years: 20-90%

≥16 years: 56-80%

Day(s) Performed

Thursday

Performing Laboratory

Mayo Clinic Laboratories in Rochester

CPT Code Information

83080 x 2

LOINC Code Information

Test ID Test Order Name Order LOINC Value
NAGS Hexosaminidase A and Total, S 87545-0

 

Result ID Test Result Name Result LOINC Value
27612 Hexosaminidase Total, S 1956-2
27613 Hexosaminidase Percent A, S 12914-8
27216 Interpretation (NAGS) 59462-2
27218 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

8 to 15 days

NY State Approved

Yes

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 in Special Instructions:

-Informed Consent for Genetic Testing (T576)

-Informed Consent for Genetic Testing-Spanish (T826)

2. Biochemical Genetics Patient Information (T602) in Special Instructions

3. If not ordering electronically, complete, print, and send a Biochemical Genetics Test Request (T798) with the specimen.