AR Repeat Analysis (Spinal & Bulbar Muscular Atrophy)
Use
AR Repeat Analysis is used to diagnose Spinal & Bulbar Muscular Atrophy (SBMA), also known as Kennedy disease, by determining the number of CAG triplet repeats in the androgen receptor (AR) gene. An accurate repeat length is critical, as SBMA is caused by expanded repeats beyond the normal range, and the results guide diagnosis and patient management.
Special Instructions
A completed GeneDx Neurology Test Requisition must accompany all orders. Send specimen (whole blood) at ambient temperature via FedEx Priority Overnight; refrigerate if not shipped the same day. Avoid frozen samples.
Limitations
Repeat numbers up to 50 repeats are reported with ±2 repeat accuracy, repeats >50 with ±5 repeats; exact counts cannot be determined for alleles >75 repeats. Accuracy may be limited by allele size, and internal standards are used to assess performance.
Methodology
PCR-based (PCR)
Biomarkers
Result Turnaround Time
null weeks
Related Documents
For more information, please review the documents below
Specimen
Whole Blood
Volume
5 mL
Minimum Volume
2 mL
Container
lavender top (EDTA) tube
Collection Instructions
Draw 5 mL whole blood in lavender‑top (EDTA) tube.
Storage Instructions
Transport at ambient temperature; refrigerate if not shipped the same day; frozen unacceptable.
Stability Requirements
| Temperature | Period |
|---|---|
| Room Temperature | Ambient (preferred): 24 hours |
| Refrigerated | Refrigerated: 7 days |
| Frozen | Unacceptable |