Hexosaminidase A, Total, Panel, White Blood Cell Count
This panel measures the total activity of hexosaminidase (including the A form) in a blood sample, alongside a white blood cell count. It is used to help evaluate for certain inherited metabolic disorders such as Tay-Sachs disease.
["The test helps determine whether hexosaminidase A activity is reduced, which can support the diagnosis of a lysosomal storage disorder."]
Key facts at a glance
- LOINC
- 87544-3
- Short code
- Hexosaminidase A & Total Pnl WBC-cCnt
- Synonyms
- Hexosaminidase A & Total Pnl WBC-cCnt
- Category
- chemistry
- Sample
- serum
- Container
- Red-top tube (SST)
- Units
- N/A
- Ref low
- 44
- Ref high
- 147
- Critical range
- 2 N/A – 30 N/A
- Fasting
- false
- Population
- adult
- Sex
- all
- Age range
- 18–65 years
- CPT
- 84075
- SNOMED
- 27550007
- Specimen volume
- 5 mL
- Stability
- Room temperature: 4h, Refrigerated: 24h, Frozen: 7d
- Hemolysis max
- 500
- Lipemia max
- 1000
- Icterus max
- 500
- TAT
- 4–24 hours
- Order
- routine
What Is Hexosaminidase A?
Hexosaminidase A is an enzyme found in the lysosomes of cells, where it helps break down certain fatty substances called GM2 gangliosides. When this enzyme is missing or not working properly, these substances build up in cells, especially in the brain and nervous system.
Why a Total Panel Is Used
Measuring total hexosaminidase alongside the A form helps laboratories interpret results more accurately. The total panel may include both hexosaminidase A and hexosaminidase B, and comparing them supports the detection of specific enzyme deficiencies.
How the Blood Sample Is Collected
A blood sample is drawn from a vein, usually in the arm, and sent to the laboratory. The sample is processed to separate white blood cells, which are then tested for enzyme activity and counted.
What the Results Can Mean
Results are interpreted by your healthcare provider in the context of your symptoms, family history, and other tests. Reduced hexosaminidase A activity may suggest a lysosomal storage disorder, while a white blood cell count provides additional information about the sample and general blood health.
Reference range
Adult: 44-147 U/LN/A
No special preparation required. Stay well hydrated.
Clinical interpretation
How abnormal results are interpreted and what conditions they suggest.
Hexosaminidase A testing is clinically important for identifying Tay-Sachs disease and related GM2 gangliosidoses. Low enzyme activity can support diagnosis, carrier detection, or prenatal evaluation when appropriate. Results should always be interpreted by a qualified clinician alongside genetic testing and clinical findings.
Short name
Hex A Total with WBC
Frequently asked questions
Does this test diagnose Tay-Sachs disease on its own?
Do I need to fast before this test?
Is the white blood cell count part of the same blood draw?
Sources
- 1
- 2Lab Tests OnlineSource
- 3
Click any link to access the full source. PubMed Central (PMC) links provide free full-text access.
This information is for educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment.
This content is for general informational and educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment. Always seek the guidance of a qualified healthcare provider with any questions you have about a medical condition, and never disregard professional medical advice or delay seeking it because of something you read here.
If you think you may have a medical emergency, call your local emergency number or go to the nearest emergency department immediately.
Medically reviewed by WellAlly Editorial Team Last reviewed August 16, 2026. · Read our editorial policy