Friedreich Ataxia (FXN) Repeat Expansion Test

Test Code

115281

CPT Codes
81284

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

8 mL whole blood collected in an EDTA (lavender-top) tube
Pediatric (0-3 Years): 2 mL

Minimum Volume

6 mL • 1 mL pediatric

Instructions

Please label each specimen tube with two forms of patient identification. These forms of identification must also appear on the requisition form.

Do not centrifuge whole blood specimens. Send original tubes. Specimens must be received Monday through Thursday. Avoid freezing.

Note: Higher blood volumes ensure adequate DNA quantity, which varies with WBC, specimen condition, and need for confirmatory testing. Patients, 0-3 years have higher WBC, yielding more DNA per mL of blood.

Transport Temperature

Room temperature

Specimen Stability

Room temperature: 10 days
Refrigerated: 10 days
Frozen: Unacceptable

Methodology
Repeat Expansion Detection by Polymerase Chain Reaction • Southern Blot

Setup Schedule

Set up: Varies; Report available: 14-28 days

Reference Range

Normal: ≤ 33 GAA trinucleotide repeats

Clinical Significance

Test is useful in the differential diagnosis for autosomal recessive cerebellar ataxia.

Performing Laboratory
Athena Diagnostics, Inc.
200 Forest Street, 2nd Floor
Marlborough, MA 01752

The CPT Codes provided in this document are based on AMA guidelines and are for informational purposes only. CPT coding is the sole responsibility of the billing party. Please direct any questions regarding coding to the payor being billed. Any Profile/panel component may be ordered separately. Reflex tests are performed at an additional charge.