Tests

ST. PAUL, Minin., Feb. 27 (UPI) — A team of U.S.-based scientists say they have developed a model using a “biological clock” to predict — with just a simple blood test — when someone is likely to develop symptoms of Alzheimer’s disease.

The results of a study published this month in the journal Nature Medicine demonstrate how, by measuring blood plasma levels of a protein in people who are not yet impaired by Alzheimer’s symptoms, researchers can predict when cognitive decline will begin within a margin of three to four years.

While there is no single, stand-alone test to diagnose Alzheimer’s today, the new method works by leveraging how levels of the protein “p-tau217” in the blood closely reflect how much amyloid plaque has built up in the brain over time. This provides doctors with a “clock” that points to when a patient may begin to experience symptoms.

Amyloid buildup in the brain may begin up to 20 years before a person starts to experience symptoms of memory and thinking issues. The plaques are a key pathological hallmark and contributing factor in Alzheimer’s disease, and, much like looking at the rings of a tree, p-tau217 levels can reveal the age of the buildup.

The authors, based at the Washington University School of Medicine in St. Louis, say their new blood test method will have immediate applications in ongoing clinical trials seeking answers to the vexing questions about what causes and what can prevent Alzheimer’s and dementia, which affect more than 7 million Americans at an estimated cost of nearly $400 billion in 2025.

Eventually, with further refinement, researchers hope the blood test could one day be used in clinical settings to easily and quickly provide predictions about the timeline of symptom onset for individual patients. The only feasible ways of doing so now are through costly brain imaging scans and invasive spinal fluid tests.

The study was part of a project headed by the Foundation for the National Institutes of Health Biomarkers Consortium, a public-private charitable partnership established by Congress in 1990 whose roster includes schools such as Washington University, life science companies including Johnson & Johnson and the Alzheimer’s Association.

Dr. Suzanne Schindler, senior author of the study and associate professor in the WashU Medicine Department of Neurology, said that while current blood tests for p-tau217 are already capable of identifying cognitively unimpaired people who might develop Alzheimer’s symptoms, they have no ability to estimate when.

Thus, they are used only for research studies and clinical trials due to legal and ethical considerations, such as the risk of causing undue stress from uncertain results.

“Our study, however, suggests it’s possible to predict when symptoms might develop using blood p-tau217,” she told UPI. “The prediction is very rough and so is still only useful in research or trials.

“We believe these predictions can be refined, but it’s unclear if they’ll become reliable enough for individual guidance without more invasive tests like spinal fluid analysis,” she cautioned.

Still, the potential of uses of the blood test are immediate when it comes to Alzheimer’s research. For instance, they could allow clinical trials of potentially preventive treatments to be performed within a shorter time period.

“Clinical trials are currently underway that are treating cognitively unimpaired individuals who test positive for blood p-tau217,” Schindler noted. “We must wait to see if these treatments delay or prevent symptom onset, but I’m hopeful based on our understanding of the disease’s biology.”

Beyond clinical trials, the blood test will aid broader Alzheimer’s research “by linking p-tau217 levels to specific brain changes, helping us disentangle whether those changes are driving cognitive impairment amid its overall complexity,” she added.

The new study “provides evidence that plasma p‑tau217 may be a reliable tool for estimating the future onset of Alzheimer’s disease symptoms,” agreed Rebecca Edelmayer, vice president of scientific engagement for the Alzheimer’s Association.

“This could transform how researchers design clinical trials and, eventually, how clinicians identify people at highest risk for cognitive decline associated with Alzheimer’s years before decline begins,” she told UPI.

While the blood test method represents a “very intriguing discovery,” it’s important to note it is not yet ready for everyday use by doctors or patients, Edelmayer cautioned, noting that its three- to four-year margin of error effectively rules out its utility for individual decision-making.

Broadly speaking, blood tests are not yet recommended for cognitively unimpaired individuals outside research settings, but even so, “this finding is an important research step because a blood test is generally much less expensive and easier to administer than a brain scan or spinal‑fluid test,” she said.

“In the future, it could help doctors and researchers identify people who may benefit from early treatments, and make clinical trials for new Alzheimer’s therapies run faster and more efficiently.”

The possibility of making a difference in the long-running battle against one of the most feared and intractable diseases in the world holds a special meaning for Schindler.

“As a memory specialist, I’ve diagnosed over 1,000 people with Alzheimer’s and witnessed firsthand its devastating effects on patients and families,” she said. “These results make me hopeful, and it’s rewarding to think this research could improve diagnosis and treatment of Alzheimer’s.”

Chinese company AutoFlight conducted a public flight demonstration for its 5-tonne-class flying car V5000 Matrix on Thursday. It can carry 10 passengers, and the company says its operating costs are one-tenth of those of traditional helicopters.

The initial production representative MQ-25 Stingray tanker drone for the U.S. Navy has completed its first low-speed taxi test. The service has said it is now targeting a first flight for the uncrewed aircraft early this year, after missing a self-imposed deadline to reach that milestone before the end of 2025.

The taxi test took place at Boeing’s facility at MidAmerica Airport, situated outside of St. Louis, Missouri, according to social media posts from the company and Naval Air Systems (NAVAIR). Navy personnel from Air Test and Evaluation Squadron 23 (VX-23) and Air Test and Evaluation Squadron 24 (UX-24), the latter of which is focused specifically on supporting the development of uncrewed aerial systems, participated in the event, per NAVAIR.

Taxing testing, with the drone moving under its own power, is a critical step toward a first flight. When exactly this milestone was achieved is not immediately clear, and TWZ has reached out to NAVAIR and Boeing for more information.

Boeing had previously announced the start of ground testing of the production representative MQ-25 last summer. A flying MQ-25 demonstrator, also known as T1, has been used in flight and ground testing in support of the Stingray program for years now. However, it is a test article that is not fully reflective of the production-standard aircraft.

Boeing MQ-25 Becomes First Unmanned Aircraft to Refuel Another Aircraft

Testing MQ-25 Aboard an Aircraft Carrier

The footage released today provides new views of the drone’s exotic top-mounted ‘flush’ air inlet and its engine exhaust inset inside the fuselage, as seen at the top of this story and below. TWZ has drawn particular attention to the inlet in the past, which speaks to the design’s other low observable (stealthy) features, as well as its overall design, despite this not being an explicit focus of the MQ-25 program.

Boeing has previously confirmed to us that the MQ-25’s design was influenced by the company’s submission to the Navy’s abortive Unmanned Carrier Launched Airborne Surveillance and Strike (UCLASS) program. UCLASS envisioned a stealthy carrier-based drone capable of performing kinetic strikes and intelligence, surveillance, and reconnaissance (ISR) missions. Despite significant work toward fielding that capability, including ground-breaking flight testing using a pair of X-47B drones built by Northrop Grumman, the Navy subsequently abandoned the UCLASS plans in favor of an uncrewed tanker. That decision, in turn, led to the MQ-25.

The video also offers a new look at the production representative Stingray configuration’s retractable sensor turret under the nose. Turrets like these typically contain a mixture of electro-optical and infrared cameras, and sometimes also have laser range finders, laser spot markers, and laser designators. In addition to its primary role as a pilotless aerial refueling platform, the Navy says the MQ-25 will have a secondary ISR function. The Stingray’s overall design opens up the possibility that it could take on other missions, including kinetic strike, in the future, as TWZ has previously explored in detail.

Boeing has otherwise been working in recent years to deliver nine pre-production Stingrays, five of which will be used for fatigue and other static testing work. The Navy plans to eventually acquire a total of 76 Stingrays, and has been most recently targeting 2027 for reaching initial operational capability (IOC) with the type.

The MQ-25 program has been beset by delays and cost growth in recent years. The original goal had been for the initial batch of pre-production Stingrays to be delivered in 2022 and for the type to reach IOC in 2024. Last year, the Navy repeatedly stressed that it was working hard to finally get to first flight before 2026.

“We will fly MQ-25 in ‘25. You can quote me on that,” Vice Adm. Daniel Cheever, Commander of Naval Air Forces, said in January 2025. “We will fly that platform in ‘25 and get that thing on a carrier in ‘26 and start integrating that thing.”

“There’s a lot of confidence in MQ-25 and [20]25. There is a ton of work to get MQ-25 and ’25,” now-retired Navy Vice Adm. Carl Chebi, then head of Naval Air Systems Command (NAVAIR), had also said last April. “70% of the capability that we deliver, [that] industry delivers to us, is late. So we’re pushing hard.”

Needless to say, the first flight schedule subsequently slipped into 2026.

These hurdles aside, Navy officials continue to be outspoken in their support of the MQ-25 program, which they see as offering critical range extension for current and future aircraft embarked on the service’s carriers. The Navy also wants the Stingrays so it can stop flying crewed F/A-18F Super Hornets in the tanker role, which makes up a significant number of their sorties while deployed, helping free up those aircraft for other missions and reducing the wear and tear on those airframes.

The Navy also regularly talks about the MQ-25 being a “pathfinder” for other future carrier-based uncrewed aviation capabilities. As far back as 2021, the service has been talking about a goal to eventually see 60 percent or more of the aircraft in carrier air wings become uncrewed.

Last year, the Navy announced a new surge in efforts to acquire a fleet of carrier-based Collaborative Combat Aircraft (CCA) drones, hiring four companies (Anduril, Boeing, General Atomics, and Northrop Grumman) to develop conceptual designs. Lockheed Martin is also now under contract to the Navy to develop an underlying common control architecture. NAVAIR has now also established a CCA-focused Future Advanced Capability (FAC) program office. The Navy previously entered into a formal agreement with the U.S. Air Force and the U.S. Marine Corps to work together on CCA developments to ensure interoperability, including the ability to seamlessly exchange control of drones during future operations.

In the meantime, beyond just getting the MQ-25 flying, the Navy still has much work to do in integrating the Stingray into routine operations. As noted, critical command and control architectures, along with related tactics, techniques, and procedures, are still being developed.

The Stingrays will also have to be woven into the existing cadence of flight deck operations, including just figuring out how to move them around amid the hustle and bustle of other activity. Carrier decks are very constrained environments physically, and present very different conditions to operate in compared to bases on land. This is true even for crewed aircraft operations, where individuals onboard can provide additional situational awareness. A wearable glove-like system that personnel could use for deck handling was notably used during testing of the X-47B. A different kind of portable control device has been used in testing of the T1 MQ-25 demonstrator in the past, as well. The video released today does not appear to offer any major new insights into how the Navy plans to maneuver the Stingray around on carrier decks.

The Navy has also been developing new force structures and training pipelines to support the MQ-25 program.

With the start of taxi-testing, the MQ-25 is at least now one step closer to its first flight.

Update: 3:12 PM EST —

Boeing and the Navy have now confirmed to TWZ that the first taxi test occurred yesterday.

“The first U.S. Navy MQ-25A Stingray is in the final stages of ground testing and completed its first taxi test yesterday,” a company spokesperson told us in a statement. “Boeing and the Navy will now conduct additional taxi tests and then complete deliberate systems level testing and review and approve the final airworthiness artifacts needed for a flight clearance. Once that’s complete and we have a suitable weather window, the aircraft will fly.”

“The [MQ-25] aircraft is now in the final stages of ground testing and successfully completed its first low-speed taxi test [on] January 29,” Navy Rear Adm. Tony Rossi, Program Executive Officer for Unmanned Aviation and Strike Weapons (PEO U&W), also told TWZ in a statement. “The team is finalizing systems testing and flight clearance, with the first flight planned once certification is complete and weather permits.”

“The MQ-25A Navy–Boeing team continues to make progress toward first flight,” Rossi added. “Over the last several months, the team has completed MQ-25A Stingray structural testing on a static aircraft, conducted initial engine runs, completed its flight-certified software, and commanded the vehicle from the Unmanned Carrier Aviation Mission Control System (UMCS).”

Contact the author: joe@twz.com