Referred Tests
| Web: | mayocliniclabs.com |
|---|---|
| Email: | mcl@mayo.edu |
| Telephone: | 800-533-1710 |
| International: | +1 855-379-3115 |
| Values are valid only on day of printing. | |
Test ID: NAGR
Hexosaminidase A and Total, Leukocytes/Molecular Reflex, Whole Blood
Useful For 
Suggests clinical disorders or settings where the test may be helpful
Carrier detection and diagnosis of Tay-Sachs disease
Recommended test for carrier detection of Tay-Sachs disease
Carrier detection and diagnosis of Sandhoff disease
Genetics Test Information Provides information that may help with selection of the correct genetic 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, Whole Blood:
-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 variant 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 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. 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 Tay-Sachs disease could be completed with MUGS testing without collecting a new specimen.
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 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 tests that may or may not be performed, at an additional charge, depending on the result and interpretation of the initial tests.
| Test ID | Reporting Name | Available Separately | Always Performed |
|---|---|---|---|
| TSDP | Tay-Sachs, Mutation Analysis | Yes | No |
Testing Algorithm Delineates situations when tests are added to the initial order. This includes reflex and additional tests.
If hexosaminidase A activity is below 63%, then molecular variant analysis will be 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 Library of PDFs including pertinent information and forms related to the test
Method Name A short description of the method used to perform the test
Heat Inactivation/Fluorometric/Semiautomated
NY State Available Indicates the status of NY State approval and if the test is orderable for NY State clients.
Reporting Name Lists a shorter or abbreviated version of the Published Name for a test
Aliases Lists additional common names for a test, as an aid in searching
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)