Ordering Recommendation

Acceptable reflexive panel for the differential diagnosis of acquired neuromuscular junction disorders. Panel includes acetylcholine receptor binding, blocking, and modulating antibodies; ganglionic acetylcholine receptor antibodies; P/Q-type and N-type voltage-gated calcium channels; voltage-gated potassium channels; titin antibody; striated muscle antibodies; and leucine-rich glioma-inactivated protein 1 antibody and contactin-associated protein-2 antibody IgG with reflex to titers.

Mnemonic
MUWA R2
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
Specimens from New York clients will be sent out to a New York DOH approved laboratory, if possible.
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
0080009 Acetylcholine Receptor Binding Antibody
Negative 0.0-0.4 nmol/L
Positive 0.5 nmol/L or greater

0099580 Acetylcholine Receptor Blocking Antibody Effective November 18, 2013
Negative: 0-26% blocking
Indeterminate: 27-41% blocking
Positive: 42% or greater blocking

0099521 Acetylcholine Receptor Modulating Antibody Effective August 20, 2012
Negative 0-45% modulating
Positive 46% or greater modulating

0092628 P/Q-Type Voltage-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

  N-Type Calcium Channel Antibody
Negative 0.0 to 69.9 pmol/L
Indeterminate 70.0 to 110.0 pmol/L
Positive 110.1 pmol/L or greater

3003020 Ganglionic Acetylcholine Receptor Antibody
Negative 0.0 - 8.4 pmol/L
Indeterminate 8.5 - 11.6 pmol/L
Positive 11.7 pmol/L or greater

2004890 Voltage-Gated Potassium Channel (VGKC) Antibody, Serum
Negative 31 pmol/L or less
Indeterminate 32-87 pmol/L
Positive 88 pmol/L or greater

2005636 Titin 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

0050746 Striated Muscle Antibodies, IgG with Reflex to Titer Less than 1:40
2009456 Leucine-Rich, Glioma-Inactivated Protein 1 Antibody, IgG with Reflex to Titer, Serum Less than 1:10
2009452 Contactin-Associated Protein-2 Antibody, IgG with Reflex to Titer, Serum Less than 1:10

Interpretive Data

Refer to report.

Compliance Category
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 detected, then a titer will be added. If VGKC is Indeterminate or Positive, LGI1 Antibody IgG and CASPR2 Antibody IgG will be added. If LGI1 antibody IgG is positive, then LGI1 antibody IgG titer will be added. If CASPR2 antibody IgG is positive, then CASPR2 antibody IgG titer will be added. Additional charges apply.

Hotline History
N/A
CPT Codes

83519 x5; 83516 x2; 86255; if reflexed, add 83516 and/or 86256 and/or 86255x2, if further reflexed add 86256 per titer

Components
Component Test Code* Component Chart Name LOINC
0050747 Striated Muscle Antibodies, IgG Screen 49692-7
0080009 Acetylcholine Binding Antibody 11034-6
0092629 P/Q-Type Calcium Channel Antibody 33980-4
0099580 Acetylcholine Blocking Antibody 42937-3
2004890 Voltage-Gated Potassium Channel Ab, Ser 41871-5
2005637 Titin Antibody
3002047 N-Type Calcium Channel Antibody 33979-6
3003019 Ganglionic Acetylcholine Receptor Ab 42233-7
* 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
Autoimmune Neuromuscular Junction Reflexive Panel