A blood test called Alzheimer's right 90 percent of the time

Researchers at Lund University in Sweden tested whether a simple blood draw could do better. They measured a protein called p-tau217 in blood samples from more than a thousand patients already being evaluated for memory problems.

Sebastian Palmqvist's team compared the blood test against the judgment of primary care doctors and dementia specialists working the normal way, without biomarker results. The blood test identified underlying Alzheimer's disease with about 90 percent accuracy. Primary care doctors reached about 61 percent, specialists about 73 percent.

The result suggested a cheap blood draw could catch Alzheimer's pathology that busy clinics miss or misdiagnose, speeding access to care and trials. The test looked for amyloid-linked brain changes, not a definitive clinical diagnosis, and still needs validation in more diverse populations before it replaces a specialist workup entirely.

A blood draw outscored two kinds of doctors.