Alzheimer’s is the most common form of dementia and is thought to affect up to 38 million people worldwide. Scientists have invented a blood test for Alzheimer’s, which could enable faster diagnosis of the disease and make treatments more effective. Diagnosing Alzheimer’s currently requires a costly brain scan, together with a spinal fluid sample taken during a painful lumbar puncture. Doctors test the spinal fluid for a particular protein specific to Alzheimer’s. The new blood test uses a specially designed antibody that binds to the same protein. It was developed by scientists at the University of Pittsburgh. The scientists say their Alzheimer’s blood test is cheaper, safer, and easier to perform though it’s still at an early stage.