A Simple, Rapid and Non-Radiolabeled Immune Assay to Detect Anti-AChR Antibodies in Myasthenia Gravis.

Objective: To assess the practicality of dot-blot testing for rapid and sensitive detection of the antiacetylcholine receptor (anti-AChR) antibodies in myasthenia gravis (MG).

Methods: In this case-control study, we tested serum specimens of 85 patients with MG, 85 healthy control individuals, and 85 patients without MG who have other autoimmune and neurological illnesses. All the serum specimens were tested for anti-AChR antibodies using 3 assays: in-house enzyme-linked immunosorbent assay (ELISA), the dot-blot assay, and commercial ELISA.

Results: In-house ELISA, commercial ELISA, and dot-blot test results were positive for anti-AChR antibodies in 65 (76.5%) patients with MG. The results of all 3 tests were negative for anti-AChR antibodies in healthy controls and patients without MG. We observed perfect concordance (K = 1, P <.001) between all 3 tests. In-house ELISA correlated significantly (r = 0.873, P <.001) with commercial ELISA. In-house ELISA and the dot-blot test demonstrated similar diagnostic performance in detecting anti-AChR antibodies.

Conclusions: The dot-blot assay is a simple, nonradioactive immune assay for rapid detection of anti-AChR antibodies in MG.