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

Test Catalog

Take Our Survey

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

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

Carrier detection and diagnosis of Tay-Sachs disease (See also NAGW / Hexosaminidase A and Total Hexosaminidase, Leukocytes and NAGS / Hexosaminidase A and Total Hexosaminidase, Serum for additional testing options).

 

Recommended test for carrier detection of Tay-Sachs disease

 

Carrier detection and diagnosis of Sandhoff disease (testing option-not the recommended test)

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

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:

-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 also can 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.

-If results indicate normal, indeterminate, or carrier status and the suspicion of Tay-Sachs disease (TSD) remains high, MUGS / Hexosaminidase A (MUGS), Serum for TSD-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. This test is appropriate for males and nonpregnant females.

-Although a leukocyte test is preferred for Tay-Sachs disease, this test can be used if it is 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.

 

MUGS / Hexosaminidase A (MUGS), 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 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, 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.

Reflex Tests Lists test(s) that may or may not be performed, at an additional charge, depending on the result and interpretation of the initial test(s)

Test IDReporting NameAvailable SeparatelyAlways Performed
TSDPTay-Sachs, Mutation AnalysisYesNo

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

If hexosaminidase A is <63%, then TSDP / Tay-Sachs Disease, Mutation Analysis, HEXA will be added and performed at an additional charge.

 

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

Heat Inactivation, Fluorometric, Semiautomated

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

Yes

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

Hexosaminidase A and Tot, WBC/Mole

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

B-N-Acetylglucosaminidase
Beta-N-Acetylglucosaminidase
GM2 Gangliosidosis
Hex A Deficiency
Hexosaminidase A
Sandhoff Carrier Screening
Sandhoff Disease
Sandhoff Disease Carrier Screening
Tay Sachs Carrier Screening
Tay Sachs Disease
Tay Sachs Disease Carrier Screening
Tay Sachs Enzyme Testing with Molecular Reflex
Tay-Sachs Carrier Screening
Tay-Sachs Disease (TSD)
Tay-Sachs Disease Carrier Screening
Tay-Sachs Enzyme Testing With Molecular Reflex
TSD (Tay-Sachs Disease)

Key