Acetylcholine Receptor Binding Antibody with reflex to Muscle-Specific Kinase (MuSK) Ab, IgG

Casandra

Casandra Test Code AR85367Version 1 (DRAFT)

Performing Lab

Lab ARUP LaboratoriesLab Test ID 3001868CPT Codes 86041, 86256, 86366

Acetylcholine Receptor Binding Antibody with reflex to Muscle-Specific Kinase (MuSK) Ab, IgG

Also known as: ACHR BIN R

Clinical Use

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Use

Approximately 85-90 percent of patients with myasthenia gravis (MG) express antibodies to the acetylcholine receptor (AChR), which can be divided into binding, blocking, and modulating antibodies. Binding antibodies can activate complement and lead to loss of AChR, while blocking antibodies may impair the binding of acetylcholine to the receptor, leading to poor muscle contraction. Modulating antibodies cause receptor endocytosis, resulting in loss of AChR expression and correlating most closely with the clinical severity of the disease. This test is intended as an initial diagnostic test when suspicion of myasthenia gravis is high.

Special Instructions

If the Acetylcholine Receptor Binding Antibody result is less than or equal to 0.4 nmol/L, then Muscle-Specific Kinase (MuSK) Ab, IgG (ARUP test code 3006198) will be added, and additional charges will apply.

Limitations

The test was developed and its performance characteristics determined by ARUP Laboratories. It has not been cleared or approved by the US Food and Drug Administration. It is performed in a CLIA certified laboratory and is intended for clinical purposes. Approximately 10-15 percent of individuals with confirmed myasthenia gravis have no measurable binding, blocking, or modulating antibodies.

Test Details

New York Approved