Last month, The US Food and Drug Administration approved a new blood test for assisting the diagnosis of Alzheimer’s disease. Produced by Roche, Elecsys pTau181 measures the concentration of a specific molecule—a phosphorylated form of the tau protein—in the blood. Tau is one of two proteins, the other being amyloid, that become malformed and accumulate in the brains of patients with certain types of dementia. It is believed that the buildup of these proteins interferes with the communication of brain cells, leading to these patients’ symptoms.
The test had already received authorization in July for marketing in Europe and is thus the first early