I've had three AChR-antibody tests (all negative). I was finally diagnosed by a single-fiber EMG (actually, I had three of those, too! The first two were inconclusive).

It's quite common to test negative for the AChR-antibodies at first, and positive later.

There are two other antibody tests you should have: MuSK and LEMS (Lambert Eaton Myasthenic Syndrom). I had one each of those. There are even more antibodies that cause MG-like symptoms, but they're not commonly tested for.

All of this is to say: definitely yes, keep testing!

Abby

My neuro-muscular Dr test me every 6 months. I started neg. then positive for binding now I'm positive for 4 different antibodies 2 1/2 years into this.
Mike

Hi, Unsure81. Welcome! It sounds like your care has been poorly managed in the past. I'm sorry about that. But this new doctor sounds like he knows what he's doing.

First, please do not "push through the fatigue!" If you push MG, it'll just push right back.

What's more important than the antibody tests right now - and what concerns me - is how you describe your breathing! It seems to me that you need to get help right away. The other specialty that works with neurology for an MG patient is pulmonology. Have you ever been assessed by a pulmonologist?

A pulmy can check your O2, do breathing tests and an arterial blood gas if necessary. My pulmy has been invaluable in the past.

If your breathing is so bad that you can't take a breath in or out, can't swallow and/or move well (generalized weakness), you need to get to an ER. Dialing 911 is best. You can't tell how quickly MG will go downhill or how bad it will get. It's a very unpredictable disease.

Antibody tests do change over time, like these guys have said. They do not necessarily reflect severity of MG. There's also the MuSK antibody test and some MGers are seronegative.

Please take it easy! You need to rest as much as you can. And do not stay out in hot weather! It can tank MG quickly.

Don't be shy about going to an ER. It sounds like you are doing pretty badly.

I hope you'll get answers soon.

Annie

I was tested in sept after a severed episode of double vision. It was negative. Double vision did not no away and in jan the dr did test again. That time it was positive. She said it has a high rate of false negative. She also suggested I use a different lab for the second one.

I was tested at diagnosis and tested positive, I was tested again 4 months post Thymectomy and tested negative......but I also felt amazing at that point.

I'm now feel terrible again and would be curious as to what the results would be now. I'm going to push for another test to see where I'm at.