Hi, and welcome. It's quite common to have a negative blood test for MG, especially in the beginning--and especially if only your eyelid is affected. Many of us here who have been diagnosed with MG have never had a positive blood test (myself included). Also, in addition to the most common antibody (AChR-antibodies) there are others you can be tested for, but probably haven't, like MuSK antibodies.

There's a much more sensitive test for MG, called a single-fiber EMG. Many of us whose blood tests are negative were diagnosed by SFEMG.

You should also know that pyridostigmine (around here we usually call it Mestinon, which is actually the brand name) is sometimes not effective for ocular MG. So if you take it and it doesn't work, that's not evidence, in itself, that you don't have MG. On the other hand, if it makes a very noticeable difference, that's strongly suggestive of MG. Mestinon has a very short half-life. For most people, the effects wear off in four hours. So if you eyelid perks up half an hour after you take the pill, but droops again after three hours, that should make you think it's the Mestinon that's causing the improvement.

I highly recommend finding a neuro-ophthalmologist. Those guys really understand MG.

Abby