September 7, 2024
The current workflow in the Massachusetts General Hospital Frontotemporal Disorders Unit and Memory Disorders Unit for the diagnostic evaluation of a patient suspected of having MCI or mild dementia due to Alzheimer’s disease (AD) or an AD related disease (ADRD) involves 1) a typical comprehensive clinical assessment by a neurologist or psychiatrist followed immediately after the visit by 2) blood labs to survey for common comorbid or contributing conditions tailored to the patient’s risk profile and then usually by 3) neuropsychological assessment and 4) structural brain imaging with MRI. Many patients have 5) an FDG PET to evaluate regional brain glucose metabolism. Many patients then undergo 6) cerebrospinal fluid examination for amyloid-beta, total tau, and phospho-tau, now considered the gold standard for consideration for disease-modifying therapy (DMT) (i.e., lecanemab or donanemab). Now that 7) amyloid PET scans are approved for Medicare reimbursement, they will be obtained from many patients since that will be used to follow response to DMT therapy. In more complex cases additional diagnostic assessments and testing may be indicated.
Although our Alzheimer’s Disease Research Center is investigating blood-based biomarkers (BBBs) in a variety of patient populations, these research results are not usable in the clinic for a variety of reasons.
As BBBs become available for clinical use, our clinicians would like to begin using them but we do not want the patient or hospital to be billed for their use because we do not yet believe they have been adequately validated in our setting, patient population, and clinical workflow.
Under the leadership of Dr. Mark Eldaief, we launched the Clinical IMpact of Blood-Based Biomarker Assays on dementia specialists’ decision-making (CIMBBBA) study. This study evaluates how our doctors use these new tests to make decisions about other kinds of testing or treatments in patients. We are evaluating clinically and commercially available BBBs in the early stage of our diagnostic workflow (step #2 above) to determine their role in potentially increasing or decreasing the priority for expensive and/or invasive assessments and testing. Once we reach a consensus on the role for BBBs in our tertiary care academic medical center clinic, we can begin to advise our colleagues in similar practices and in primary care about the role of these emerging tools in clinical practice.