Modern use of biomarkers in geriatric medicine

The use of biomarkers is ubiquitous in medicine. For the diagnosis of neurodegenerative dementias such as Alzheimer's disease, frontotemporal dementia, and dementia with Lewy bodies, the following biomarkers obtained from neuroimaging or cerebrospinal fluid are currently in use: regional brain loss (atrophy) from structural magnetic resonance imaging, and brain hypometabolism and hypoperfusion using positron emission tomography. Defining valid biomarkers for frailty is challenging, primarily because there is currently no generally accepted definition of frailty, and the concordance between different frailty scales is limited. The difference between frailty and sarcopenia is complicated to explain, given that several of the criteria commonly used to measure both coincide. The most recent addition of ageing phenotypes of interest to geriatric medicine is intrinsic capacity (IC). Research into the predictive quality of the IC concept and associated biomarkers that predict IC trajectories is only starting.