Muscle Weakness Autoimmune Reflexive Panel
2005640
Ordering Recommendation
Acceptable reflexive panel for diagnosing myasthenia gravis. Panel contains binding, blocking, and modulating antibodies; voltage-gated calcium and potassium channels; titin antibody; and SMA IgG screen with titer.
Mnemonic
MUWA R PAN
Methodology
Quantitative Radioimmunoassay/Qualitative Radiobinding Assay/Semi-Quantitative Flow Cytometry/Semi-Quantitative Indirect Fluorescent Antibody
Performed
Refer to individual components
Reported
2-8 days  
New York DOH Approval Status
This test is New York DOH approved.
Submit With Order
Specimen Required
Patient Preparation
  
Collect
Serum separator tube (SST).  
Specimen Preparation
Separate serum from cells ASAP or within 2 hours of collection. Transport 2 mL serum. (Min: 1 mL)  
Storage/Transport Temperature
Refrigerated.  
Unacceptable Conditions
Plasma. Contaminated, hemolyzed, or severely lipemic specimens.  
Remarks
  
Stability
Ambient: 48 hours; Refrigerated: 2 weeks; Frozen: 1 year  
Reference Interval
 
 
Test Number Components Reference Interval
0080009Acetylcholine Receptor Binding Antibody Negative: 0.0-​0.4 nmol/L
Positive:  0.5 nmol/L or greater
0099580Acetylcholine Receptor Blocking Antibody Effective November 18, 2013
 
Negative: 0-​26% blocking
Indeterminate: 27-​41% blocking
Positive: 42% or greater blocking
0099521Acetylcholine Receptor Modulating Antibody Negative: 0-​45% modulating
Positive: 46% or greater modulating

Effective August 20, 2012
0092628Voltage-​Gated Calcium Channel (VGCC) Antibody Effective November 14, 2011
 
Negative 0.0 to 24.5 pmol/L
Indeterminate 24.6 to 45.6 pmol/L
Positive 45.7 pmol/L or greater
2004890Voltage-​Gated Potassium Channel (VGKC) Antibody Effective April 18, 2011
 
Negative 31 pmol/L or less
Indeterminate 32-​87 pmol/L
Positive 88 pmol/L or greater
2005636Titin Antibody Effective January 17, 2012
 
Titin Antibody
Negative 0.00-​0.45 IV
Indeterminate 0.46-​0.71 IV
Positive 0.72 IV or greater
0050746Striated Muscle Antibodies, IgG with Reflex to Titer Screen:  < 1:40 No antibodies detected.
Titer:    < 1:40 No antibodies detected.
Interpretive Data
Titin Antibody: The presence of titin antibody is associated with late onset of myasthenia gravis (MG) and a variable risk for thymoma. Titin antibody may be detected in 20-40 percent of all patients with MG; higher frequency in older population as a whole.

Striated Muscle Antibodies, IgG: In the presence of acetylcholine receptor (AChR) antibody, striated muscle antibodies, which bind in a cross-striational pattern to skeletal and heart muscle tissue sections, are associated with late-onset myasthenia gravis (MG). Striated muscle antibodies recognize epitopes on three major muscle proteins, including: titin, ryanodine receptor (RyR) and Kv1.4 (an alpha subunit of voltage-gated potassium channel [VGKC]). Isolated cases of striated muscle antibodies may be seen in patients with certain autoimmune diseases, rheumatic fever, myocardial infarction, and after some cardiotomy procedures.

See Compliance Statement B: www.aruplab.com/CS
Statement B: This test was developed and its performance characteristics determined by ARUP Laboratories. The U.S. Food and Drug Administration has not approved or cleared this test; however, FDA clearance or approval is not currently required for clinical use. The results are not intended to be used as the sole means for clinical diagnosis or patient management decisions.
 
Note
If Acetylcholine Receptor Binding Antibody result is greater than 0.4 nmol/L or Acetylcholine Receptor Blocking Antibody result is greater than 26 percent, then Acetylcholine Receptor Modulating Antibody will be added. If Striated Muscle Ab is greater than or equal to 1:40, then a titer will be added. Additional charges apply.
CPT Code(s)
83519; 83516; if reflexed, add 83516 x2; 83519 x2; 86255; if reflexed, add 86256
Components
Component Test Code*Component Chart NameLOINC
0050747Striated Muscle Antibodies, IgG Screen49692-7
0050748Striated Muscle Antibodies, IgG Titer29998-2
0080009Acetylcholine Binding Antibody11034-6
0092629Voltage-Gated Calcium Channel (VGCC) Ab31024-3
0099580Acetylcholine Blocking Antibody42937-3
2004890Voltage-Gated Potassium Channel (VGKC)Ab41871-5
2005637Titin Antibody 
* Component test codes cannot be used to order tests. The information provided here is not sufficient for interface builds; for a complete test mix, please click the sidebar link to access the Interface Map.
Aliases
  • AChR Binding Antibody
  • AChR Antibody
  • Anti-Skeletal Muscle IgG Antibodies
  • Anti-Striated Antibody
  • anti-tintin Ab
  • Muscle (Skeletal) Antibodies
  • Muscle nicotinic Acetylcholine Receptor
  • Myasthenia Gravis Antibodies
  • Myoid Antibody
  • Skeletal Muscle Antibodies
  • Striational Antibodies
  • VGCC Ab
  • VGKC Ab
  • Voltage-Gated Calcium Channel Antibody
  • Voltage-Gated Potassium Channel Antibody