MS Biomarkers: Three Caveats to Bear in Mind
MSAA’s Chief Medical Officer Barry Hendin, MD, is a neurologist and MS specialist in Phoenix, Arizona. According to Dr. Hendin, while people with MS have ample cause to be excited about how biomarkers can help assess their status and guide their treatment, it is important to keep three facts in mind.
While biomarkers are important parts of the picture, they aren’t the whole picture.“As clinicians, we treat the patient in front of us, not a lab report number or an MRI finding,” Dr. Hendin says, noting that MS providers look at a patient’s symptoms, physical and cognitive function, neurological exam results and other factors, as well as biomarker results, to form a comprehensive view of the patient’s health and proceed accordingly. “Pattern recognition is critical in neurology,” Dr. Hendin adds, noting that neurologists look for alignment among different findings to support a diagnosis or treatment plan rather than putting undue emphasis on a single test result. |
Not all established biomarkers are created equal.Different biomarkers have different degrees of usefulness in clinical decision-making. One reason for this, Dr. Hendin explains, is the issue of sensitivity versus specificity. “In diagnosing conditions, sensitivity refers to the proportion of actual positive cases that a test is able to identify, while specificity references the actual number of negative cases it can recognize. “With high sensitivity, you have fewer false negatives, meaning fewer missed cases. With high specificity you have fewer false positives, or wrong diagnoses. The ideal is to have a test that has both high sensitivity and high specificity, but in the real world, there are often trade-offs involved. Based on their sensitivity and specificity, some tests are more valuable to us than others.” |
Biomarkers have to prove themselves over time – and in different clinical settings and patient populations.The identification of a new biomarker is exciting for researchers, clinicians, and patients alike, but not everyone is familiar with what the laboratory scientists and MS providers know all too well: that it’s a long road from discovery to integration into clinical care. “It takes time to move from a laboratory-based study or even a good-sized clinical trial to having a full understanding of how reliable a biomarker is in people with different forms of MS or of different ages, genders, or ethnic backgrounds,” Dr. Hendin explains. Beyond those purely clinical considerations, real-world factors also help determine the usefulness of a biomarker. “For example, a fluid biomarker measured with a simple blood draw generally is going to be preferable to one that requires a lumbar puncture to obtain spinal fluid.” |