MuSK and LRP4 Antibodies Panel

Test Code
MUSKLRP4


Quest Code
1490


CPT Codes
86366, 86255

Preferred Specimen
2 mL serum


Minimum Volume
0.5 mL


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


Transport Container
Transport tube


Transport Temperature
Refrigerated (cold packs)


Specimen Stability
Room temperature: 72 hours
Refrigerated: 25 days
Frozen: 25 days


Methodology
Immunofluorescence Assay (IFA) • Radioimmunoassay (RIA)

Setup Schedule
As needed


Report Available
14-21 days


Reference Range
See Laboratory Report


Clinical Significance
Detects anti-MuSK (muscle specific receptor tyrosine kinase) and anti-LRP4 (low density lipoprotein receptor-related protein 4) in the sera of patients with Myasthenia Gravis (MG). MuSK is a transmembrane endplate polypeptide involved in a signaling pathway that maintains the normal functional integrity of the neuromuscular junction (NMJ). The LRP4 protein activates MuSK kinase activity and promotes the clustering of the acetylcholine receptor (AChR) and its stabilization at the NMJ. Approximately 8% to 10% of all MG cases and 20% to 50% of the generalized MG cases who lack anti-AChR have anti-MuSK. Anti-LRP4 antibodies are detected in the serum of approximately 9.2% (range 2% to 50%) of MG patients who are negative for both anti-AChR and anti-MuSK.


Performing Laboratory
Athena Diagnostics, Inc.
200 Forest Street, 2nd Floor
Marlborough, MA 01752-3023




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.