For how we live.
The approved tests are for patients already showing cognitive decline. Used on the worried well, a positive result mostly signals a risk that may never become disease — and no treatment follows from it.
US government metrologists sent one homogenised faecal standard to seven consumer testing services. Species counts came back ranging from 20 to 1,701 for the same material.
Three February papers push plasma p-tau217 past detection: clock models estimating years to symptom onset, four assays compared head to head, and a real-world audit of what the result changes.
At a Mayo Clinic cohort of 252 patients, 40% of amyloid-negative people tested positive. The manufacturer says it has found a manufacturing problem and put the product on hold.
The external validation of a micro-RNA signature outperformed imaging in 971 symptomatic patients. How it would perform in a lower-prevalence population is the question the study does not answer.
Two BMJ reviews found high-risk usability problems in 18 of 30 tests, and use judged contrary to evidence-based guidance for 11 of the 19 conditions covered.