New tests that measure beta-amyloid and tau proteins in cerebrospinal fluid - which surrounds the brain and spinal cord - could help doctors diagnose early Alzheimer's so people with the disease can take new and emerging medications that may slow progression. One test, cleared by the FDA in 2022, compares levels of two beta-amyloids that build up in the brain with Alzheimer's. Other test for Alzheimer's biomarkers have also received FDA clearance in the past two years. In studies, results of the tests were comparable to PET brain scans used to detect Alzheimer's brain changes.