Serum from adult cardiac arrest survivors was sampled prospectively at 24, 48, and 72 h post-arrest and analyzed for peak-levels of Alzheimer disease markers (p-tau181, total tau, amyloid β [Aβ40 and Aβ42]), and the neurodegenerative biomarker neurofilament light (NfL). The gene discussed is MAPT; the disease is Alzheimer disease.