Acetylcholine receptor (ACR) antibodies
| Category | Immunology |
|---|---|
| Test background |
The most sensitive and specific test for myasthenia gravis is the presence of ACR. Myasthenia gravis is a neuromuscular disorder characterised by weakness and fatigability of skeletal muscles. The aetiology involves a numerical decrease in the number of available acetylcholine receptors at the neuromuscular junctions due to an antibody-mediated autoimmune attack. Not all patients who have myasthenia gravis have positive ACR titres. ACR antibodies are seen in 45 % to 65 % of patients with ocular myasthenia and in approximately 90 % of patients with generalised myasthenia gravis. The degree of 'positivity' for the test results does not correlate with the severity of disease. |
| Clinical Indications |
Degenerative neuromuscular disease Respiratory crises Dysphagia Facial weakness |
| Reference range | 0-5 x 10-10 mol |
| Sample & container required | RST (rust top) |
| Sample volume | 5-10 mL (1 mL serum) |
| Turnaround time | 28 days |
| Notes | Not currently performed in house; this test is referred to the Immunology Department at Oxford. |