Blood tests that identify specific antibodies linked to myasthenia gravis (MG) are not consistently used in the United States, and this variation may affect how patients are diagnosed and treated, according to a study published recently in the Journal of the Neurological Sciences.
In this large real-world study of 5,788 adults newly diagnosed with MG between January 2018 and June 2022, fewer than half received any documented serologic antibody testing, even though these tests help confirm the diagnosis and guide therapy.
This study used insurance claims linked to laboratory results to examine testing patterns for three antibodies: acetylcholine receptor, muscle-specific kinase and LRP4. Overall, 2,590 patients, or 44.7%, had at least one valid antibody test.
“Our results establish a baseline understanding of variation in diagnostic and testing patterns and associated treatment in MG from which to launch improvement initiatives,” stated this study’s authors.
Read more about testing and diagnosis for MG
Among those tested, 56.3% were seronegative, meaning no antibodies were detected, while 42.4% were positive for acetylcholine receptor antibodies. Only 1.1% were positive for muscle-specific kinase antibodies and 0.2% for LRP4 antibodies. Importantly, many seronegative patients were not fully evaluated, as 56.6% were tested only for acetylcholine receptor antibodies.
Who made the diagnosis strongly influenced whether testing occurred. Patients diagnosed by neurologists were far more likely to receive antibody testing than those diagnosed by non-neurologists, with testing rates of 54.8% versus 33.0%.
More than two-thirds of individuals diagnosed by non-neurologists never received serologic testing. This matters because MG symptoms can mimic other conditions and antibody results can clarify the diagnosis.
Patients often first presented with eye-related symptoms such as drooping eyelids or double vision, yet only 6.2% were diagnosed by ophthalmologists. Most diagnoses occurred during outpatient visits, and electromyography testing was uncommon, recorded in just 12.2% of patients. Testing was also less likely among people living in rural areas, those with higher medical complexity and those insured by Medicaid or commercial plans compared with Medicare.
Despite limited testing, treatment was common. Nearly 70% of patients received MG–specific therapy within the first year after diagnosis. Acetylcholinesterase inhibitors and corticosteroids were the most frequently used treatments, even among patients who were untested or seronegative. This suggests many patients start medications without clear antibody information to guide decisions.
For patients, these results highlight the importance of asking about antibody testing, especially when care is managed outside neurology. More complete testing may reduce diagnostic delays, avoid unnecessary treatments and help ensure therapies are better matched to the specific type of MG.
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