Spinal Muscular Atrophy (SMA)

Casandra

Casandra Test Code LC49905Version 1 (DRAFT)

Performing Lab

Lab LabcorpLab Test ID 481630CPT Code 81329

Spinal Muscular Atrophy (SMA)

Also known as: SMA testing, SMA types I, II, III, SMN1 copy number analysis

Clinical Use

Order Test

Use

This test is used for carrier screening for spinal muscular atrophy and diagnostic testing for individuals suspected of having spinal muscular atrophy.

Special Instructions

For fetal specimens including cord blood, the specific test 'Spinal Muscular Atrophy (SMA), Fetal Analysis [481651]' should be ordered. Test orders need to include an attestation that the provider has obtained the patient's informed consent for genetic testing. It's important not to eat, drink, smoke, or chew gum 30 minutes prior to sample collection.

Limitations

This test does not detect germline mosaicism and cannot identify large chromosomal aberrations such as rearrangements and gene fusions. It does not evaluate variants in genes not included in the test nor does it consider inter/intragenic interactions or repeat expansions. Results may be impacted by rare genetic variants, pseudogene interference, or identity issues such as mislabeled samples.

Test Details

Methodology

PCR-based (qPCR)

Biomarkers

SMN1

Gene

Copy Number • Mutation • Categorical (e.g., Positive / Negative / Indeterminate)

LOINC Codes

Result Codes

42784-9
31208-2
89993-0
42349-1
41053-0
54449-7
53039-4
8262-8
62385-0
55752-0
8251-1
49549-9
36908-2
75608-0
72486-4
51969-4

Result Turnaround Time

8-14 days

Specimen

Whole Blood

Volume

8.5 mL

Minimum Volume

3 mL

Container

Yellow-top (ACD-A) tube or lavender-top (EDTA) tube

Collection Instructions

Standard phlebotomy; follow PurFlock buccal swab kit or Oragene Dx 500 saliva kit collection instructions. Do not eat, drink, smoke, or chew gum 30 minutes prior to collection.