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HelpTest 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 | Special Container |
|---|---|---|---|
| Varies | Ambient (preferred) | ||
| Frozen | |||
| Refrigerated | |||
Reference Values
An interpretive report will be provided.
Interpretation
All detected alterations are evaluated according to American College of Medical Genetics recommendations.(1) Variants are classified based on known, predicted, or possible pathogenicity and reported with interpretive comments detailing their potential or known significance.
Clinical Reference
1. Richards S, Aziz N, Bale S, et al: Standards and guidelines for the interpretation of sequence variants: a joint consensus recommendation of the American College of Medical Genetics and Genomics and the Association for Molecular Pathology. Genet Med 2015 May;17(5):405-424
2. Gravel RA, Kaback MM, Proia RL, et al: The GM2 gangliosidosis. In The Metabolic and Molecular Bases of Inherited Disease. Eigth edition. Edited by CR Scriver, AL Beaudet, WS Sly, et al. New York, McGraw-Hill Book Company, 2001, pp 3827-3876
3. ACOG Committee on Genetics: ACOG Committee Opinion #318; Screening for Tay-Sachs disease. Obstet Gynecol 2005;106(4):893-894
Day(s) Performed
Performed weekly
Report Available
14 to 20 daysPerforming Laboratory
Mayo Clinic Laboratories in Rochester
Test Classification
This test was developed and its performance characteristics determined by Mayo Clinic in a manner consistent with CLIA requirements. It has not been cleared or approved by the US Food and Drug Administration.CPT Code Information
81406
LOINC Code Information
| Test ID | Test Order Name | Order LOINC Value |
|---|---|---|
| HEXAZ | HEXA Gene, Full Gene Analysis | 76033-0 |
| Result ID | Test Result Name | Result LOINC Value |
|---|---|---|
| 53943 | Result Summary | 50397-9 |
| 53944 | Result | 82939-0 |
| 53945 | Interpretation | 69047-9 |
| 53946 | Additional Information | 48767-8 |
| 53947 | Specimen | 31208-2 |
| 53948 | Source | 31208-2 |
| 53949 | Released By | 18771-6 |
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.