Myasthenia Gravis Antibody Profile
The Myasthenia Gravis Antibody Profile measures three types of Acetylcholine receptor (AChR) antibodies and Striated Muscle antibodies in the blood to screen for Myasthenia Gravis.
Description
This test measures the three types of Acetylcholine receptor (AChR) antibodies and Striational antibodies in the blood to diagnose Myasthenia Gravis (MG). In addition, this test helps to determine if an individual may have MG or another condition with similar symptoms.
MG is an autoimmune disorder that causes chronic muscle fatigue and weakness throughout the body. Normally, individuals can move their muscles voluntarily when an impulse is transmitted to the nerve endings and prompts the release of a substance called acetylcholine. The acetylcholine binds to the receptors between the nerves and muscles (neuromuscular junction), triggering muscle movement. However, individuals with MG immune systems produce antibodies that obstruct communication between the nerves and muscles. These antibodies hinder muscle movement and cause rapid muscle fatigue or MG.
The three AChR antibodies found in individuals with MG are:
- AChR Binding antibodies
- AChR Blocking antibodies
- AChR Modulating antibodies
Although individuals with MG usually test positive for AChR antibodies, there are cases where individuals with MG do not have these antibodies. In those cases, a Striated Muscle Antibody test may be performed, also known as an anti-MuSK antibody test. This condition is sometimes called MuSK MG.
Common signs or symptoms of MG include:
- weak eye movement
- drooping eyelids
- blurred or double vision
- a change in facial expression
- difficulty swallowing
- shortness of breath
- impaired speech
- weakness in the arms, hands, fingers, legs, and neck
Individuals may order this test if they are experiencing signs and symptoms that suggest MG or if they are experiencing symptoms but test negative for AChR antibodies. Additionally, this test can help distinguish MG from other conditions that may cause similar symptoms.