Test library
Hexosaminidase A Test
The Tay-Sachs carrier test measures the activity of the enzyme hexosaminidase A to determine whether a person carries a gene change linked to Tay-Sachs disease. It can also support a diagnosis when symptoms are present.
Order Tay-Sachs Disease Testing
Order online and visit a local collection site, or choose an at-home kit where available. No referral and no insurance required.
Order Tay-Sachs Disease Testing- Typical turnaround
- 1-3 business days
- Starting price
- From $1798
- Results
- Confidential, online
Quick answer
The Tay-Sachs carrier test uses a blood sample to measure the activity of hexosaminidase A, an enzyme involved in breaking down certain fats in the nervous system. Reduced enzyme activity can indicate that a person carries a gene change associated with Tay-Sachs disease. The test supports carrier screening and, when symptoms are present, can help evaluate the condition. A qualified healthcare provider interprets the result and offers genetic counseling.
What this test measures
Tay-Sachs disease is an inherited condition caused by changes in the HEXA gene, which carries instructions for the enzyme hexosaminidase A. This enzyme helps break down a fatty substance called GM2 ganglioside in nerve cells. When the enzyme is missing or reduced, the substance builds up and damages the nervous system. The condition is passed in an autosomal recessive pattern.
The test measures hexosaminidase A activity in a blood or serum sample. In carrier screening, reduced activity can suggest a person carries one altered copy of the gene, while a diagnosis involves more detailed enzyme and genetic testing. Because enzyme levels can be affected by other factors, abnormal results are usually confirmed with additional testing, including DNA analysis.
The test may be ordered for people with a family history of Tay-Sachs disease, for couples planning a pregnancy who want carrier screening, or for individuals in groups where certain gene changes are more common. Carriers are usually healthy and may not know their status. Genetic counseling is recommended before and after testing to explain results and options.
- Hexosaminidase A (Hex A) enzyme activity
- Total hexosaminidase activity
- Hexosaminidase A percentage of total
- HEXA gene mutation analysis when added
- Common HEXA variants when tested
- Enzyme activity relative to reference range
- Genetic counseling referral markers
Why people order this test
- Carrier screening for people with a family history
- Preconception or prenatal carrier testing for couples
- Support the evaluation of symptoms consistent with Tay-Sachs disease
- Confirm reduced enzyme activity with genetic testing
- Provide information before genetic counseling
- Screen individuals in groups where certain variants are more common
How to prepare
No fasting is required. A blood sample is drawn from a vein, usually at the arm. Some laboratories ask for a specific sample type for enzyme testing, so follow the collection instructions provided with the order.
Understanding your results
Results are typically available within one to three business days, though genetic confirmation may take longer. Reduced hexosaminidase A activity can indicate carrier status or disease, but results are confirmed with additional testing. A qualified healthcare provider and genetic counselor interpret the findings and explain what they mean.
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Frequently Asked Questions
What is Tay-Sachs disease?
It is an inherited condition caused by changes in the HEXA gene. Without enough hexosaminidase A enzyme, fatty substances build up in nerve cells and cause progressive neurological problems.
What does the carrier test measure?
It measures the activity of the hexosaminidase A enzyme. Lower activity can suggest a person carries a gene change linked to the condition.
How is the inheritance pattern described?
Tay-Sachs is autosomal recessive, meaning a child is affected only when both parents pass on a changed copy of the gene. Carriers typically have one changed copy and no symptoms.
Does the test require fasting?
No fasting is required for this test.
Will I need genetic counseling?
Genetic counseling is commonly recommended before and after testing so results can be explained and options discussed in full.
Can the test diagnose the condition?
Enzyme testing can support a diagnosis when symptoms are present, but results are usually confirmed with genetic testing. A healthcare provider makes the final assessment.
Ready to get tested?
Order online and visit a collection site near you, or choose a mail-in kit. No referral and no insurance required.
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