Blood-based biomarkers will likely lead to earlier diagnoses and therapies (plenty of which are in the pipeline), as well as offer reassurance to those who appear symptomatic for Alzheimer’s but don’t have the disease.
It should also make such testing more accessible. Until now, diagnoses have been based on cerebrospinal fluid biomarkers and PET scans. Like the word “concertize” in classical music, these are serviceable but unwieldy—hence the search for something better.
“Blood-based biomarkers are so much less invasive, and so their use is skyrocketing in the U.S.,” says Dr. Frykman.
Prior to these recent developments, says Dr. Tran, “We at best had some biomarkers for traumatic brain injury,” though there is overlap between the two. “We’ve seen Alzheimer’s biomarkers show up initially with the CSF-based tests,” including p-tau181, total tau, and Aβ42. Despite strong interest from the Alz-heimer’s community, however, “You couldn’t realistically adopt that in a cost-effective manner.” And while CSF biomarkers still offered rule-out value versus waiting for a PET scan, testing was largely the province of large reference laboratories. “So everyone was eager to get access to the FDA-approved blood-based test[s],” he says.
Dr. Tran is especially enthusiastic about the p-tau181 test because it’s been approved for use in primary care. “It moves it closer to the patient per se,” he says, providing answers more quickly versus awaiting an appointment with a neurologist or other specialist.
The benefits are already becoming evident, Dr. Frykman says. “Specifically, the p-tau217 alone has very high accuracy. And it performs really well in both mild dementia as well as in the MCI [mild cognitive impairment] population.” The current generation of tests are not appropriate for use in a cognitively normal population with amyloid pathology, since the pretest probability is not sufficiently high. But future generations of these tests might be useful in other settings and with different populations.
As the conversation around these biomarkers shakes out, it’s not a stretch to think about the current tests as the equivalent of spring training. Even the most casual baseball fan feels the enthusiasm at the start of the season; in AD research, better markers seem the equivalent of playing baseball well into October. Of course, even as spring hopes are eternal, there remain the genuine difficulties that emerge after Opening Day.
But the work has to begin somewhere. “You always start with an imperfect point,” says Dr. Shaw. “And then much of the learning curve is after the test is introduced.”
In other words: Play ball!
One challenge is working with these particular proteins. Think of it as sort of a reverse Hubble telescope: With these proteins, Dr. Frykman, says, “We’ve never gone so deep into the proteome and measured something that’s so very, very low abundance.” Such proteins are highly susceptible to different interferences, which are only now being fully appreciated.
“In the future, more work will have to be done,” Dr. Frykman says. This includes investigating how the markers work in various subpopulations of patients. One example comes from a recent study in JAMA Neurology, which suggests there are sex differences in p-tau217, tau aggregation, and cognitive decline (Coughlan GT, et al. Published online Feb. 16, 2026. doi:10.1001/jamaneurol.2025.5670).
Each of the biomarkers tells different, deeper parts of the Alzheimer’s story, says Dr. Tran, including looking at direct axonal injury and looking at the formation of amyloid plaques that can cause disease. In theory, he says, the p-tau217/Aβ42 ratio test improves the performance of both biomarkers, working synergistically. But p-tau217 also appears to perform well on its own, and it might detect disease earlier than p-tau181. But, as noted, only p-tau181 is currently approved for use in primary care.