The key to diagnosing seronegative myasthenia gravis is listening

Living with myasthenia gravis (MG) can feel like starring in a mystery movie I never auditioned for. One minute, I’m moving just fine, and the next, my muscles behave like someone flipped my power switch to low. Anyone with MG knows this rhythm all too well, but my road to diagnosis came with an added twist: my blood tests insisted that I was perfectly healthy.

This is how I discovered that I had seronegative MG, the form of the disease that doesn’t show up in standard blood tests. I often refer to it as sero-unknown MG because the science surrounding it is evolving faster than I can keep up with. Researchers are still identifying new antibodies related to MG, and each discovery adds another puzzle piece to a picture that has been incomplete for far too long.

When doctors look for MG, they first test for well-known antibodies like acetylcholine receptor (AChR), muscle-specific kinase (MuSK), or lipoprotein receptor-related protein 4 (LRP4). If those antibodies are present, the diagnosis becomes relatively straightforward. However, about 10%-15% of MG patients don’t have these antibodies. Our bodies exhibit all the classic signs of MG, yet our lab tests remain normal.

My first negative test felt like the medical system was telling me that the weakness in my arms, the choking on my food, and the slurred speech were merely tricks of my imagination.

Anyone familiar with my earlier columns knows that my diagnostic journey was not a quick one. I spent a good chunk of time rushing to appointments, only to experience long periods of uncertainty. Each new test delivered the same message: nothing to see here. Meanwhile, my body was crying out for help.

When a doctor finally said, “Your tests are negative, but your symptoms are consistent with MG,” it felt like someone had opened a window in a stuffy room. I finally had a name for what was happening, which brought a kind of relief I still struggle to put into words.

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Treatments aren’t always accessible

Here’s the frustrating part: People with seronegative MG receive the same treatments as those who test positive. Medications such as pyridostigmine, steroids, immunosuppressants, intravenous immunoglobulin (IVIG), and plasmapheresis can also be effective in managing symptoms. IVIG has been a significant help in my own care.

However, obtaining these treatments’ approval from doctors or insurance companies can feel like a full-time job. Some doctors remain skeptical of seronegative MG because the textbook version of the disease does not align with our lab results. Insurance companies often echo that skepticism, using it as a reason to deny referrals. I’ve heard numerous stories of people whose treatment requests were rejected because they lacked the “right” antibody. This creates a detrimental loop: No antibody means no approval, no approval means no treatment, and no treatment means symptoms spiral until the patient is barely functioning.

MG doesn’t become any less real just because a lab hasn’t caught up with the science.

I am aware of how fortunate I am to be treated through the Veterans Affairs system. My neurologist there listens first and looks at the lab work second. He treats the patient sitting in front of him rather than just following a checklist. I wish this approach were the norm for everyone. Too many people with civilian insurance have to fight tooth and nail for the therapies that help them stay on their feet.

Trusting your body

The invisibility of seronegative MG creates its own kind of ache. When your tests indicate nothing is wrong, some people start to believe it. That disbelief can seep into conversations, appointments, and even your own mind if you are not cautious.

Meanwhile, the illness persists. My legs have given out while I was trying to make supper. My arms have stopped functioning halfway through washing my hair. I’ve had days when chewing a sandwich required more energy than making it. None of this was imaginary, nor was it “just stress.” It was MG in full force.

The hopeful part is that science is slowly catching up. With each newly identified antibody, researchers gain a better understanding of the many forms MG can take. Perhaps one day, we won’t need a “seronegative” category at all because the tests will finally reflect the complete picture.

Until then, many of us live in the gray area where our symptoms tell the truth, even when lab results say “negative.” If you are still searching for a diagnosis or fighting to be believed, I hope you cling to what your body is telling you. You are not imagining things.

Seronegative, seropositive, or sero-unknown — every person with MG deserves care, compassion, and treatment that helps them reclaim their strength and live their best life.

Note: Myasthenia Gravis News is strictly a news and information website about the disease. It does not provide medical advice, diagnosis, or treatment. This content is not intended to be a substitute for professional medical advice, diagnosis, or treatment. Always seek the advice of your physician or other qualified health provider with any questions you may have regarding a medical condition. Never disregard professional medical advice or delay in seeking it because of something you have read on this website. The opinions expressed in this column are not those of Myasthenia Gravis News or its parent company, Bionews, and are intended to spark discussion about issues pertaining to myasthenia gravis.