New blood tests could help doctors diagnose AlzheimerSA国际影视传媒檚 disease faster and more accurately, researchers reported Sunday SA国际影视传媒� but some appear to work far better than others.

ItSA国际影视传媒檚 tricky to tell if memory problems are caused by AlzheimerSA国际影视传媒檚. That requires confirming one of the diseaseSA国际影视传媒檚 hallmark signs SA国际影视传媒� buildup of a sticky protein called beta-amyloid SA国际影视传媒� with a hard-to-get brain scan or uncomfortable spinal tap. Many patients instead are diagnosed based on symptoms and cognitive exams.

Labs have begun offering a variety of tests that can detect certain signs of AlzheimerSA国际影视传媒檚 in blood. Scientists are excited by their potential but the tests arenSA国际影视传媒檛 widely used yet because thereSA国际影视传媒檚 little data to guide doctors about which kind to order and when. The U.S. Food and Drug Administration hasnSA国际影视传媒檛 formally approved any of them and thereSA国际影视传媒檚 little insurance coverage.

SA国际影视传媒淲hat tests can we trust?SA国际影视传媒� asked Dr. Suzanne Schindler, a neurologist at Washington University in St. Louis whoSA国际影视传媒檚 part of a research project examining that. While some are very accurate, SA国际影视传媒渙ther tests are not much better than a flip of a coin.SA国际影视传媒�

Demand for earlier AlzheimerSA国际影视传媒檚 diagnosis is increasing

More than 6 million people in the United States and millions more around the world have AlzheimerSA国际影视传媒檚, the most common form of dementia. Its telltale SA国际影视传媒渂iomarkersSA国际影视传媒� are brain-clogging amyloid plaques and abnormal tau protein that leads to neuron-killing tangles.

New drugs, Leqembi and Kisunla, can modestly slow worsening symptoms by removing gunky amyloid from the brain. But they only work in the earliest stages of AlzheimerSA国际影视传媒檚 and proving patients qualify in time can be difficult. Measuring amyloid in spinal fluid is invasive. A special PET scan to spot plaques is costly and getting an appointment can take months.

Even specialists can struggle to tell if AlzheimerSA国际影视传媒檚 or something else is to blame for a patientSA国际影视传媒檚 symptoms.

SA国际影视传媒淚 have patients not infrequently who I am convinced have AlzheimerSA国际影视传媒檚 disease and I do testing and itSA国际影视传媒檚 negative,SA国际影视传媒� Schindler said.

New study suggests blood tests for AlzheimerSA国际影视传媒檚 can be simpler and faster

Blood tests so far have been used mostly in carefully controlled research settings. But a new study of about 1,200 patients in Sweden shows they also can work in the real-world bustle of doctorsSA国际影视传媒� offices SA国际影视传媒� especially primary care doctors who see far more people with memory problems than specialists but have fewer tools to evaluate them.

In the study, patients who visited either a primary care doctor or a specialist for memory complaints got an initial diagnosis using traditional exams, gave blood for testing and were sent for a confirmatory spinal tap or brain scan.

Blood testing was far more accurate, Lund University researchers reported Sunday at the AlzheimerSA国际影视传媒檚 Association International Conference in Philadelphia. The primary care doctorsSA国际影视传媒� initial diagnosis was 61% accurate and the specialistsSA国际影视传媒� 73% SA国际影视传媒� but the blood test was 91% accurate, according to the findings, which also were published in the Journal of the American Medical Association.

Which blood tests for AlzheimerSA国际影视传媒檚 work best?

ThereSA国际影视传媒檚 almost SA国际影视传媒渁 wild WestSA国际影视传媒� in the variety being offered, said Dr. John Hsiao of the National Institute on Aging. They measure different biomarkers, in different ways.

Doctors and researchers should only use blood tests proven to have a greater than 90% accuracy rate, said AlzheimerSA国际影视传媒檚 Association chief science officer Maria Carrillo.

TodaySA国际影视传媒檚 tests most likely to meet that benchmark measure whatSA国际影视传媒檚 called p-tau217, Carrillo and Hsiao agreed. Schindler helped lead an unusual direct comparison of several kinds of blood tests, funded by the Foundation for the National Institutes of Health, that came to the same conclusion.

That type of test measures a form of tau that correlates with how much plaque buildup someone has, Schindler explained. A high level signals a strong likelihood the person has AlzheimerSA国际影视传媒檚 while a low level indicates thatSA国际影视传媒檚 probably not the cause of memory loss.

Several companies are developing p-tau217 tests including ALZpath Inc., Roche, Eli Lilly and C2N Diagnostics, which supplied the version used in the Swedish study.

Who should use blood tests for AlzheimerSA国际影视传媒檚?

Only doctors can order them from labs. The AlzheimerSA国际影视传媒檚 Association is working on guidelines and several companies plan to seek FDA approval, which would clarify proper use.

For now, Carrillo said doctors should use blood testing only in people with memory problems, after checking the accuracy of the type they order.

Especially for primary care physicians, SA国际影视传媒渋t really has great potential to help them in sorting out who to give a reassuring message and who to send on to memory specialists,SA国际影视传媒� said Dr. Sebastian Palmqvist of Lund University, who led the Swedish study with LundSA国际影视传媒檚 Dr. Oskar Hansson.

The tests arenSA国际影视传媒檛 yet for people who donSA国际影视传媒檛 have symptoms but worry about AlzheimerSA国际影视传媒檚 in the family SA国际影视传媒� unless itSA国际影视传媒檚 part of enrollment in research studies, Schindler stressed.

ThatSA国际影视传媒檚 partly because amyloid buildup can begin two decades before the first sign of memory problems, and so far there are no preventive steps other than basic advice to eat healthy, exercise and get enough sleep. But there are studies underway testing possible therapies for people at high risk of AlzheimerSA国际影视传媒檚, and some include blood testing.

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The Associated Press Health and Science Department receives support from the Howard Hughes Medical InstituteSA国际影视传媒檚 Science and Educational Media Group. The AP is solely responsible for all content.

Lauran Neergaard, The Associated Press