Tests Involved in a Diagnostic Workup of Multiple Sclerosis
Peter L. Salgo, MD: You alluded to some things that I want to pin down, radiologic studies: CT [computed tomography], MRI [magnetic resonance imaging]. And something that nobody’s mentioned yet, the LP [lumbar puncture]. That used to be one of the standard diagnostic tests. Do we still do it? Is it necessary?
Patricia K. Coyle, MD, FAAN, FANA: Yes. I really think you need to do a work-up if you’re making a diagnosis of MS [multiple sclerosis]. That is selective blood work, that is MR imaging of the brain and the rest of the central nervous system. We would routinely image cervical and thoracic spinal cord by an MRI scan. CT is worthless.
Peter L. Salgo, MD: I was going to ask that.
Patricia K. Coyle, MD, FAAN, FANA: MRI. And then we do a lumbar puncture on everybody in whom we’re working up. I practice in a Lyme endemic area, so that also comes up. Now that may be debatable. But since there’s no diagnostic biomarker, there’s no single test, you want really a complete assessment, and the spinal fluid is very helpful.
Peter L. Salgo, MD: If there’s no biomarker, what are you looking for?
Patricia K. Coyle, MD, FAAN, FANA: Positive CSF [cerebrospinal fluid]-specific oligoclonal bands. That is the key test. And then, of course, you can rule out Lyme disease and a marked pleocytosis or elevated protein, which would be red flags against the diagnosis of MS, and you can check for other things.
Thomas P. Leist, MD, PhD: The important thing underlying the diagnosis of multiple sclerosis is fulfilling dissemination in space and dissemination in time. And with the 2017 criteria for multiple sclerosis, the 2017 McDonald Criteria, it is now possible to establish dissemination in time. Because things have occurred over time by showing a positive cerebrospinal fluid examination. And so, the data are important because they allow more individuals after the first event to be diagnosed with MS.
Peter L. Salgo, MD: When you say blood test, what are you looking for in a blood test?
Patricia K. Coyle, MD, FAAN, FANA: For example, I would check vitamin D 25-hydroxy and vitamin B12. If I was working up somebody for relapsing MS, I’m going to send a cell-based aquaporin-4 IgG and MOG-IgG [myelin oligodendrocyte glycoprotein] assay on their blood to rule out NMO [neuromyelitis optica] spectrum disorder.
Peter L. Salgo, MD: This is getting expensive. Are you going to pay for all this?
Maria Lopes, MD, MS: Well, the diagnosis, once you label this individual with MS, that is in and of itself a pretty significant cost in terms of what follows. So absolutely. Everything is so important in terms of what Dr Coyle and Dr Leist have outlined in terms of confirming the diagnosis, making sure that that is indeed what it is. It’s life changing. And so as a payer, we’re going to rely on specialists. And I think perhaps even the need for general neurologists to understand the nuances so that we can confirm the diagnosis. Because everything evolves from that point on.
Peter L. Salgo, MD: But are you going to say: We’re not going to pay for diagnostic test A, B, or C because of history or physical findings?
Maria Lopes, MD, MS: Not at all. The MRIs typically do require prior authorization.
Peter L. Salgo, MD: Why?
Maria Lopes, MD, MS: The cost, right?
Peter L. Salgo, MD: I know.
Maria Lopes, MD, MS: But obviously if you’re trying to rule out MS, this is usually covered. I love what Dr Coyle also said: CTs are worthless and they are obviously expensive. It’s also obviously exposure to an x-ray that you don’t need, etcetera. So what you should do is the package of tests that really do confirm the diagnosis.
Peter L. Salgo, MD: Let’s create—I know you’ve already created—a package that you would approve, maybe with a phone call for prior approval. I’m getting the sense MRI is in that package.
Maria Lopes, MD, MS: Yes.
Peter L. Salgo, MD: What blood test? The blood test she wants?
Maria Lopes, MD, MS: Blood tests that are obviously routine.
Patricia K. Coyle, MD, FAAN, FANA: TSH [thyroid-stimulating hormone], ANA [antinuclear antibody].
Maria Lopes, MD, MS: Absolutely.
Patricia K. Coyle, MD, FAAN, FANA: Anticardiolipin, antiphospholipid, things that can mimic MS that are in the differential.
Maria Lopes, MD, MS: And none of this, by the way, requires prior authorization. You mentioned rule out Lyme disease with an LP. We want the LP to be done. Many times, unfortunately, they’re not.
Peter L. Salgo, MD: The LP is useful, you’ll approve it.
Maria Lopes, MD, MS: Absolutely.
Peter L. Salgo, MD: For patients it’s a scary name. We’re going to do a spinal tap. In practice, it’s not that awful. It’s straightforward.
Patricia K. Coyle, MD, FAAN, FANA: No, an epidural is way worse. When I mention that to a lot of people who have had epidurals, they’re shocked.