A study of 327 people with suspected myasthenia gravis (MG) found that cell-based antibody tests, particularly a live cell-based assay, were more accurate than an enzyme-linked immunosorbent assay (ELISA) for detecting acetylcholine receptor antibodies.
The findings, published recently in Neurology, are important because antibody testing is a key part of diagnosing MG, yet different testing methods can produce different results.
“Our findings are consistent with a growing body of evidence demonstrating that [cell-based antibody tests] outperform ELISA assays for [acetylcholine receptor-antibodies] detection,” the study’s investigators said.
What are acetylcholine receptor antibodies?
Acetylcholine receptors (AChRs) are proteins found on the surface of muscle cells at the neuromuscular junction. In people with AChR autoantibodies, the body mistakenly thinks the AChR receptors are foreign and marks them for the immune system to destroy, leading to muscle weakness. AChR antibodies are the most common in MG and are found in around 80% to 85% of patients.
Researchers prospectively evaluated adults and children at four Italian centers between July 2023 and December 2025. Of 368 eligible patients, 342 were enrolled and 327 remained in the final analysis after exclusions. The participants had a median age of 63 years; just over half were women. MG was diagnosed in 152 patients, including 68 with ocular MG and 84 with generalized MG. The other 175 patients had different diagnoses.
Among patients with MG, acetylcholine receptor antibodies were detected in 109 patients (71.7%) using live cell-based assay, 105 (69.1%) using fixed cell-based assay and 97 (63.8%) using ELISA. The difference was especially notable in ocular MG, where sensitivity — how well the tests identified patients with MG — was 60.3% for live cell-based assay, 54.4% for fixed cell-based assay and 45.6% for ELISA. For generalized MG, sensitivity was 80.9% for both cell-based assays and 78.6% for ELISA.
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Specificity, which reflects how well a test correctly identifies people without the disease, differed substantially. Both cell-based assays had 97.7% specificity compared with 69.1% for ELISA. Among 175 patients without MG, ELISA incorrectly detected acetylcholine receptor antibodies in 54 (30.9%), whereas the cell-based assays were positive in only 4 (2.3%). Of 32 patients with false-positive results who were followed for a median of 11.5 months, none developed MG during follow-up.
The study also found that the live cell-based assay was slightly more accurate overall than the fixed cell-based assay, while both performed better than ELISA. This difference was especially apparent in patients with ocular MG, in whom live and fixed cell-based tests were more reliable than ELISA. MuSK antibody testing performed similarly across all three methods, with no meaningful differences between the tests.
For patients, the findings mean that the type of antibody test used may influence whether a blood test supports an MG diagnosis. A positive ELISA result does not necessarily mean that a person has MG, particularly when clinical findings do not fit the disease. Cell-based testing may provide more dependable results, especially for people with ocular symptoms. However, antibody testing remains only one component of diagnosis, which also relies on the neurologic examination, electrophysiologic testing and sometimes response to treatment.
Read more about MG testing and diagnosis
