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Test ID: MUGS    
Hexosaminidase A (MUGS), Serum

NY State Approved Indicates the status of NY State approval and if the test is orderable for NY State clients.

Yes

Useful For Suggests clinical disorders or settings where the test may be helpful

Second-order test for diagnosing the B1 variant of Tay-Sachs disease

 

This test should be ordered when the patient exhibits symptoms of Tay-Sachs disease, but has tested as normal, indeterminate, or carrier by either NAGS / Hexosaminidase A and Total Hexosaminidase, Serum or NAGW / Hexosaminidase A and Total Hexosaminidase, Leukocytes

Genetics Test Information Provides information that may help with selection of the correct test or proper submission of the test request

This test (MUGS) is the recommended test for diagnosis and carrier testing for the B1 variant of Tay-Sachs disease and is performed on serum using the natural substrate. It 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. 

 

The following tests are also available for diagnostic and carrier testing for Tay-Sachs and Sandhoff diseases.

 

NAGR / Hexosaminidase A and Total, Leukocytes/Molecular Reflex:

-This is the recommended test for carrier testing for Tay-Sachs disease.

-Testing begins with hexosaminidase A and total enzyme analysis. If the results are consistent with an affected or carrier individual, Tay-Sachs mutation analysis will automatically be performed on the original specimen.

-This is not the recommended test for Sandhoff disease; however, if the results are suggestive of Sandhoff disease or carrier status, this will be indicated in the interpretive comment along with recommendations for additional testing. Follow-up testing for Sandhoff must be ordered separately.

-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 is the recommended test for diagnosis and carrier testing for Sandhoff disease. This test can also be used for diagnosis and carrier testing for Tay-Sachs disease.

-Results for hexosaminidase A and total enzyme analysis are reported with recommendations for additional testing when appropriate. All follow-up testing with the exception of MUGS must be ordered separately on new specimens. If the suspicion for Tay-Sachs disease remains high, MUGS can typically be added and performed on the same specimen.

-This test is not appropriate for pregnant females. This test is appropriate for males and nonpregnant females.

-Although a leukocyte test is preferred for Tay-Sachs disease (TSD), this test can be used if it is potentially difficult to obtain enough blood to perform testing, as may be the case with infants. Additionally, the biochemical workup for TSD could be completed with MUGS testing without collecting a new specimen.

Testing Algorithm Delineates situation(s) when tests are added to the initial order. This includes reflex and additional tests.

The following algorithms are available in Special Instructions:     

Tay-Sachs Disease Carrier Testing Protocol

Tay-Sachs and Related Disorders Diagnostic Testing Algorithm

Special Instructions and Forms Describes specimen collection and preparation information, test algorithms, and other information pertinent to test. Also includes pertinent information and consent forms to be used when requesting a particular test

Method Name A short description of the method used to perform the test

Fluorometric Manual Method Using 4-MUGS Substrate

Reporting Name A shorter/abbreviated version of the Published Name for a test; an abbreviated test name

Hexosaminidase A (MUGS), S

Aliases Lists additional common names for a test, as an aid in searching

B 1 Variant
B-1 Variant
B1 Variant
GM2 Gangliosidosis

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