Test Details & Preparation
Test details and preparation:
- An acetylcholine receptor (AChR) antibody test is used to help diagnose myasthenia gravis (MG) and to distinguish it from other conditions that may cause similar symptoms, such as chronic muscle fatigue and weakness.
- AChR antibodies are autoantibodies produced by the immune system that mistakenly target proteins called acetylcholine receptors that are located on skeletal muscle fibers.
- AChR antibodies impede communication between nerves and skeletal muscles, inhibit muscle contraction, and cause rapid muscle fatigue by preventing activation of the acetylcholine receptors.
- The test is ordered when any person show symptoms of MG such as:
- Drooping eyelid
- Double vision
- Decreased eye movement control
- Difficulty swallowing, chewing, with choking, drooling and gagging
- Slurred speech
- Weak neck muscles
- Trouble holding up head
- Difficulty breathing
- Difficulty walking and an altered gait
- Specific muscle weakness but normal feelings/sensations
- Muscle weakness that worsens with sustained effort and improves with rest
- The test is done by taking a blood sample from the vein using the needle.
- No such preparation is needed for the test
Results:
- AChR antibodies are not normally present in the blood, the normal range is 0.0-0.4 nmol/L.
- Presence of any antibodies may indicate autoimmune response. Certain conditions ay include:
- Myasthenia gravis (MS)
- Thymomas (tumour originating form the epithelial cells of the thymus)
- Positive in people who are being treated with drugs such as penicillamine
- Small cell lung cancer autoimmune liver disease, and with
- Lambert-Eaton myasthenic syndrome (a condition associated with interference with the release of acetylcholine from the nerve ending)
- Certain other follow-up tests must be done to confirm any condition.
