A B C D E F G H I J K L M N O P Q R S T U V W X Y Z # |
HEXA Gene Sequencing
Test Code16612
CPT Codes
81406
Physician Attestation of Informed Consent
This germline genetic test requires physician attestation that patient consent has been received if ordering medical facility is located in AK, DE, FL, GA, IA, MA, MN, NV, NJ, NY, OR, SD or VT or test is performed in MA.
Preferred Specimen
5 mL whole blood collected in an EDTA (lavender-top) tube
Minimum Volume
3 mL
Other Acceptable Specimens
Cultured cells collected from amniotic fluid or cultured chorionic villi collected in two (x2) separate T-25 Flasks
Instructions
Whole blood: Normal phlebotomy procedure. Specimen stability is crucial. Store and ship room temperature immediately. Do not freeze.
Transport Temperature
Room temperature
Specimen Stability
Whole blood (preferred)
Room temperature: 14 days
Refrigerated: 14 days
Frozen: Unacceptable
Cultured cells or chorionic villi
Room temperature: 24 hours
Refrigerated: Unacceptable
Frozen: Unacceptable
Room temperature: 14 days
Refrigerated: 14 days
Frozen: Unacceptable
Cultured cells or chorionic villi
Room temperature: 24 hours
Refrigerated: Unacceptable
Frozen: Unacceptable
Methodology
Next Generation Sequencing
FDA Status
This test was developed and its analytical performance characteristics have been determined by Quest Diagnostics. It has not been cleared or approved by the U.S. Food and Drug Administration. This assay has been validated pursuant to the CLIA regulations and is used for clinical purposes.
Setup Schedule
Set up: As needed; Report available: 28 days following set up
Limitations
This test will identify greater than 99% of disease-causing mutations. It will also identify the known pseudodeficiency variants that are not associated with the disease but which lead to reduced enzyme activity when the standard enzyme assay is used to measure Hex A activity. Large rearrangements (deletions/insertions) are rare and not detectable by this test method. If no mutation is found by the testing procedure, it does not mean that the risk of carrying or developing TSD is not present. It simply means that this risk is significantly reduced.
Reference Range
See Laboratory Report
Clinical Significance
Tay-Sachs disease (TSD) is a progressive neurodegenerative disease. It is caused by pathogenic variants in the HEXA gene. Gene sequencing would be appropriate for individuals who have had a positive or equivocal Tay-Sachs enzyme carrier result and are negative for a panel of common pathogenic variants.
Performing Laboratory
Quest Diagnostics Nichols Institute-San Juan Capistrano, CA |
33608 Ortega Highway |
San Juan Capistrano, CA 92675-2042 |