- Blood test for Alzheimer’s. When blood amyloid levels were combined with another major Alzheimer's risk factor—the presence of the genetic variant APOE4—the accuracy of the blood test was 88% when compared to brain imaging and 93% when compared to spinal tap. https://medicine.wustl.edu/news/blood-test-for-alzheimers-highly-accurate-in-large-international-study/ 37 comments science