What can cause a false positive repetitive nerve stimulation test? i have symptoms of myasthenia gravis (arm and leg weakness, double vision). 1st was abnormal (decrement) 2nd was normal. is mg possib

Many Possibilities: These issues are powerfully dependent on the situation and there are many variables; there is no way to provide an excellent answer, especially from a distance. Study: http://en.Wikipedia.Org/wiki/bayes%27_theorem and http://en.Wikipedia.Org/wiki/false_positive_paradox and http://en.Wikipedia.Org/wiki/false_negative#type_ii_error for some understanding.

another opinion?: Myasthenia gravis is a grave diagnosis please get another test from another institution to confirm or exclude.