Supplied Credit: Supplied Source KnownSydney will become the front line of earlier Alzheimer’s detection with an Australian-first blood test that can deliver results in as little as 18 minutes and identify disease-related changes up to 20 years before symptoms appear. Camera Icon Researchers said the blood test can detect disease-related changes linked to Alzheimer’s up to 20 years before symptoms appear. She said research showed the blood test had similar levels of accuracy to PET and CSF testing. “We know these protein changes occur decades before symptom onset and that can be detected on this blood test. “Anything that gives us the ability to diagnose it earlier through things such as a simple blood test is just as amazing.