negative blood test for antibodies
 

I'm quoting AnnieB3's post here in its own thread, because so many MG patients test negative for MG antibodies, which can delay or even prevent their diagnosis. I've seen different statistics about how many of us are seronegative, but my totally anecdotally based unscientific impression is that the numbers given are way too low. And think of it this way: if the factoid is "15% of MG patients are seronegative," that only really means "15% of MG patients who are diagnosed in spite of being seronegative are seronegative." Since being seronegative makes it difficult to get a diagnosis, then it follows that the true number of seronegative MG patients is significantly higher. Am I making sense here?

Seronegative patients only get a diagnosis if their other symptoms are text-book (and the text-books don't know everything!) or if they have access to a very knowledgeable and open-minded specialist. It's a known fact that 100% of patients with atypical MG don't have typical MG.

Abby

Abby, I honestly think that when MG patients are doing badly it's because the antibodies are busy attacking the NMJ.

And you're right, there is nothing 100% about this disease. Probably why it messes with so many neuro's heads because doctors like things to be predictable. The neuro who diagnosed me once said that he has seen MG patients in a wheelchair test negative to the SFEMG and MG patients who look and are clinically just fine test highly positive on the SFEMG. It would be interesting to compile all of this "negative/positive" info and see how the antibody levels correlate to that - if they even do!

Are there any seropositive patients who've seen their antibodies go down when they get worse? Go up?

Maybe I just have too much time on my hands. ;)

Annie

Abby, I think you have fully understood the complexity involved.

Well, there's this:

http://www.blackwellpublishing.com/p...mcqs/jun05.pdf

Abby

Contemplate this, Abby or anyone else. How much does a person's metabolism come into play? If you have a higher metabolism, like guys do, does it circulate antibodies more? And how does edema, which floods fluids into spaces not available for blood testing, or other medical issues impact the test?

And you're right, saying that 15% of MGers test negative for antibodies (ACh or MuSK) is not an obvious and accurate statement. You know that MGers are not all getting diagnosed because of the seroneg category and lack of info by regular neuros. I really hate statistics, like Bell curves. They often don't do anyone any good.

Interesting. My PCP (he's the one treating me for MG) thinks that there are undiscovered antibodies for MG and that might be what I'm dealing with. What's your opinion on that? Anyone? He also said it's probably not that unusual for the levels to go up and down in some people.

I'm off to get the MUSK test today. Crossing my fingers that it's positive as I think I may be able to find a neuro that way. Although I have to say that I love my PCP!

My first test was highly positive, second one negative, the one I just had in the hospital was positive.

The middle one was done at an MDA clinic. The neuro I saw there said, based on my test, he didn't think I had MG. This was despite the fact I had brought in my highly positive test from Athena labs with me. He wanted me to have an EMG which I've had before and consider a torture test. I switched to another neuro. I have every possible symptom and respond well to Mestinon. In fact I can't breathe without it.

I was really offended. He wrote a letter to my referring neuro (who was moving to CA) that he didn't think I had MG. I went on to my 3rd neuro, who is now treating me. I was just hospitalized for a week with an MG exacerbation. Inpatient, they wanted to do acetylcholine levels two days in a row to see if they were rising or not. Stupid, I know. Anyway they ended up drawing only one (they probably figured out the test doesn't come back right away) but that one was positive, so now I have two positive tests. I have another one that was drawn at my first appt with current neuro I still have to get results on.

Also, this second positive test was drawn after two days of IVIG, meaning I'd just been flooded with healthy antibodies. Research shows IVIG can make your test result falsely negative.

So out of four tests I've had done, I know 2/3 are positive, have yet to get results on the 4th.

Well, Abby, this antibody BS is getting ridiculous. A friend of ours, who is in her 80's but doing well, has had two positive MG antibody tests (binding). Mayo did the 2nd one. She has Lymes too. They are chalking it up to the Lymes. Lymes does not cause MG antibodies! I know why they're doing it, because she can't tolerate Mestinon and can't do immunotherapy due to previous skin cancer. And, well, you know, IVIG is too expensive and why throw that money away on someone who is old.

Lymes is painful but it won't kill you like MG can. This issue is making me completely nuts. And no one would DARE question a Mayo doctor. Well, except for me, that is. :cool: And probably a few of you guys!

Annie

Shalynn, Yes, there are more "areas" in the neuromuscular junction that are open for "attack." Titin and Ryanodine are only two of the many posibilities. A lot of people are working on figuring it out. Good luck with the MuSK test.

Tracy, I have to wonder if IVIG flushes out the antibodies from their NMJ hidey-holes. ;) Therefore making them available for the blood test (instead of hanging out in your tissues).