Via Neurophilosophy and Mind Hacks, news of new progress toward a blood test that may someday be used to diagnose Alzheimer’s disease (AD) and mild cognitive decline. The study is published in the most recent issue of Nature Medicine:

A molecular test for Alzheimer’s disease could lead to better treatment and therapies. We found 18 signaling proteins in blood plasma that can be used to classify blinded samples from Alzheimer’s and control subjects with close to 90% accuracy and to identify patients who had mild cognitive impairment that progressed to Alzheimer’s disease 2–6 years later. Biological analysis of the 18 proteins points to systemic dysregulation of hematopoiesis, immune responses, apoptosis and neuronal support in presymptomatic Alzheimer’s disease.

This test measures levels of proteins in blood plasma, and could certainly be used alongside nucleic-acid based tests such as this assay of white blood cell mRNA expression proposed last year. As I pointed out at that time, it’s likely that such tests could be made even more accurate if every patient had individual baseline measurements taken in earlier life, before any hint of dementia had emerged; this would allow physicians to distinguish between patients who had always been at one end of the population distribution and those who had recently undergone changes in biomarker levels.