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Huntington Disease (HD) CAG Repeat Expansion
Ordering Recommendation
Use to confirm a diagnosis of Huntington disease (HD) in symptomatic individuals. May be used for presymptomatic testing in adults with a family history of HD.
New York DOH Approval Status
Specimen Required
Lavender (EDTA), pink (K2EDTA)
Transport 2 mL whole blood. (Min: 1 mL)
Refrigerated. Also acceptable: Ambient.
A completed HD-specific consent form, signed by the patient (or legal guardian) and physician, is required for all specimens. Testing for asymptomatic patients under the age of 18 years is not offered. Presymptomatic patients are strongly encouraged to be tested through a counseling program approved by the Huntington Disease Society of America at 800-345-4372. Call Genetics Processing with additional questions at 800-242-2787 ext. 3301.
Room temperature: 1 week; Refrigerated: 1 month; Frozen: Unacceptable
Methodology
Polymerase Chain Reaction (PCR) / Capillary Electrophoresis
Performed
Varies
Reported
7-10 days
Reference Interval
Interpretive Data
Refer to report.
Laboratory Developed Test (LDT)
Note
Hotline History
Hotline History
CPT Codes
81271
Components
| Component Test Code* | Component Chart Name | LOINC |
|---|---|---|
| 3016909 | Huntington Disease Specimen | 31208-2 |
| 3016910 | Huntington Disease Allele 1 | 49637-2 |
| 3016911 | Huntington Disease Allele 2 | 49638-0 |
| 3016912 | Huntington Disease Interpretation | 50621-2 |
Aliases
- HD genetic testing
- HTT genetic testing
