AChR-Seronegative Myasthenia Gravis Evaluation

Last Modified: 2/2/2022 1:15:52 PM

Medical Necessity Documentation:  
Client Notes:  
Patient Preparation:  
Specimen Requirements:

2.0 mL Serum from a SST Gold Top Tube

Collection Instructions: Please label each specimen tube with two forms of patient identification. These forms of identification must also appear on the requisition form
Minimum Volume: 0.5 mL Serum
Transport & Storage: Temperature/Stability: 72 hours Ambient
25 days Refrigerated (Transport)
25 days Frozen
Reference Range: Refer to Interpretive Results
Critical Ranges:  
Test Comments:  
Methodology: Immunofluorescence Assay (IFA), Radioimmunoassay
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

Documentation: Disease test for: Myasthenia Gravis (MG)
Custom Panel: No


Turn Around Time: 9 to 16 days
Days Performed: Wednesday
Sites Performed: Quest - Valencia to Athena Diagnostics
PHL Test Code: MUSKP
EPIC Test Code: IMO5538
Send Out Test Code: 1490
Alternate Test Names: MuSK and LRP4 Antibodies Panel
Included Tests: LRP4 Autoantibody Test; MuSK Antibody Test
CPT Coding: 83519, 86255 | *ERRO, CKWEB

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