ARUP's Laboratory Test Directory
| 0099521: Acetylcholine Receptor Modulating Antibody |
| Test Mnemonic: ACHRMOD | |
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Methodology: Radioreceptor Assay
Performed: Mon-Sat Reported: 2-4 days |
| Specimen Required: | |
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Collect: One 4 mL SST.
Transport: 0.5 mL serum at 2-8°C. (Min: 0.3 mL) Submit specimen in an ARUP Standard Transport Tube. Pediatric Collection/Transport: 0.3 mL serum at 2-8°C. Remarks: Separate serum from cells ASAP. Unacceptable Conditions: Severely lipemic, contaminated, or hemolyzed specimens. Stability: After separation from cells: Ambient: 2 hours; Refrigerated: 1 week; Frozen: 1 month (avoid multiple freeze/thaw cycles) |
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| Reference Interval: |
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Negative: 0-20% modulation Indeterminate: 21-25% modulation Positive: 26% or greater modulation |
| Interpretive Data: | |
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Approximately 85-90% of patients with myasthenia gravis (MG) express antibodies to the acetylcholine receptor (AChR), which can be divided into binding, blocking, and modulating antibody. Binding antibody can activate complement and lead to loss of AChR. Blocking antibody may impair AChR binding to the receptor, leading to poor muscle contraction. Modulating antibody causes receptor endocytosis resulting in loss of AChR expression, which correlates most closely with clinical severity of disease. Approximately 10-15% of individuals with confirmed myasthenia gravis have no measurable binding, blocking, or modulating antibody.
Please refer to Statement B in the Compliance Statements section in the front of the Laboratory Test Directory. |
| CPT Code(s): | |
| 83519 |