Ordering Recommendation

Preferred test to identify carriers of Tay-Sachs disease. Preferred test to identify carriers of Sandhoff disease. Can use to evaluate symptomatic patients for Tay-Sachs disease or Sandhoff disease. Use in pregnant individuals, individuals who use oral contraceptives or hormone replacement therapy, individuals with liver or autoimmune disease, or individuals with a previous inconclusive HEX A enzyme test in plasma/serum. 




Quantitative Fluorometry




2-9 days

New York DOH Approval Status

This test is New York DOH approved.

Specimen Required

Patient Preparation

Yellow (ACD).

Specimen Preparation

Do not transfer whole blood to other containers. Transport 3 mL whole blood. (Min: 1.0 mL)

Storage/Transport Temperature

Room temperature. Also acceptable: Refrigerated.

Unacceptable Conditions

Whole blood received greater than 3 days from collection. Grossly hemolyzed specimens.


Clinical information is needed for appropriate interpretation. Additional required information includes age, gender, diet (e.g.TPN therapy), drug therapy, and family history. Biochemical Genetics Patient History Form is available on the ARUP Web site at https://www.aruplab.com/patienthistory or by contacting ARUP Client Services.


Ambient: 3 days; Refrigerated: 3 days; Frozen: Unacceptable

Reference Interval

Effective November 18, 2013

Greater than or equal to 63 percent

Interpretive Data

Refer to report.

This test was developed and its performance characteristics determined by ARUP Laboratories. It has not been cleared or approved by the US Food and Drug Administration. This test was performed in a CLIA certified laboratory and is intended for clinical purposes.

Compliance Category

Laboratory Developed Test (LDT)


This test is used for the diagnosis of Tay-Sachs disease and can also be used to identify carriers for this disorder. Carrier screening is offered to individuals of Ashkenazi Jewish descent because of the high incidence of the disease in this population.

Hotline History


CPT Codes



Component Test Code* Component Chart Name LOINC
2008126 Hexosaminidase A Percent in Leukocytes 23825-3
2008127 Hexosaminidase Total, Leukocytes 50759-0
2008128 Hexosaminidase in Leukocytes Interp 21328-0
* Component test codes cannot be used to order tests. The information provided here is not sufficient for interface builds; for a complete test mix, please click the sidebar link to access the Interface Map.


  • HEXA enzyme testing
  • Hexosaminidase A and Total, leukocytes
Hexosaminidase A Percent and Total Hexosaminidase in Leukocytes (Change effective as of 02/22/22: Refer to 3004486 in the February Hotline)