Concentrating on High-value Alzheimer's Needs to Get to an End Act of 2019 or the CHANGE Act of 2019 This bill modifies the requirements under Medicare for diagnosing and treating Alzheimer's disease and other cognitive impairments in older adults. Specifically, the bill expands the cognitive impairment detection benefit during annual wellness visits to require the use of validated detection tools and documentation of the results in the patient's medical record. Further, when a cognitive impairment is detected, the patient must be referred to an appropriate diagnostic service provider and other specified supports. Additionally, the Centers for Medicare and Medicaid Services must implement Medicare policies that increase the identification and response to patients' Alzheimer's disease risk factors and incentivize providers to utilize high-quality cognitive impairment diagnosis practices. The Government Accountability Office also must conduct a study of policies that may accelerate progress in Alzheimer's disease research and enhance the quality of care for individuals diagnosed with Alzheimer's disease.