Order Code HEXAZ Tay-Sachs Disease, HEXA Gene, Full Gene Analysis, Varies
Useful For
Second-tier test for confirming a biochemical diagnosis of Tay-Sachs disease (TSD)
Carrier testing of individuals with a family history of TSD but an affected individual is not available for testing or disease-causing mutations have not been identified
Testing individuals with enzyme activity consistent with carrier status but negative molecular testing by a panel of common mutations
Special Instructions
Method Name
Polymerase Chain Reaction (PCR) Amplification/DNA Sequencing
Reporting Name
HEXA Gene, Full Gene AnalysisSpecimen Type
VariesShipping Instructions
Specimen preferred to arrive within 96 hours of draw.
Specimen Required
Patient Preparation: A previous bone marrow transplant from an allogenic donor will interfere with testing. Call 800-533-1710 for instructions for testing patients who have received a bone marrow transplant.
Specimen Type: Whole blood
Container/Tube:
Preferred: Lavender top (EDTA) or yellow top (ACD)
Acceptable: Any anticoagulant
Specimen Volume: 3 mL
Collection Instructions:
1. Invert several times to mix blood.
2. Send specimen in original tube.
Specimen Minimum Volume
0.5 mL
Specimen Stability Information
Specimen Type | Temperature | Time |
---|---|---|
Varies | Ambient (preferred) | |
Frozen | ||
Refrigerated |
Reference Values
An interpretive report will be provided.
Method Description
Bidirectional sequence analysis is performed to test for the presence of a mutation in all coding regions and intron/exon boundaries of the beta-hexosaminidase A gene (HEXA).(Unpublished Mayo method)
Day(s) Performed
Performed weekly
Performing Laboratory

CPT Code Information
81406
Testing Algorithm
Tay-Sachs and Related Disorders Diagnostic Testing Algorithm
Forms
1. New York Clients-Informed consent is required. Please document on the request form or electronic order that a copy is on file. An Informed Consent for Genetic Testing (T576) is available in Special Instructions.
2. Molecular Genetics: Biochemical Disorders Patient Information (T527) in Special Instructions.
3. If not ordering electronically, complete, print, and send a Biochemical Genetics Test Request (T798) with the specimen.