Immunostick ELISA for rapid and easy diagnosis of myasthenia gravis.

A rapid and simple immunostick immunosorbent ELISA has been developed for the diagnosis of myasthenia gravis. It is based on coating immunosticks with the major myasthenia gravis autoantigens acetylcholine receptor (AChR) or MuSK and it can be performed in <1 h, in a non-specialized examination place by non-skilled personnel. The resulting chromogen precipitate on the sticks, evaluated by eye, was proved a reliable indication of the presence of autoantigen-specific autoantibodies. Although this assay is mostly qualitative, compared to the results obtained from the gold-standard radioimmunoprecipitation assays, its specificity for anti-AChR antibodies was 99.1% (102/103 negative sera) and its sensitivity was 91.1% (72/79) or 97.5% (77/79) depending on counting the 5 ambiguous sera as negative or positive, respectively. Smaller scale experiments suggested that the method is efficient for anti-MuSK antibodies, and may also be used with whole blood instead of serum.