The encouraging findings come amid larger efforts to develop a cheap, simple blood test that could quickly diagnose Alzheimer’s patients without forcing people to undergo more expensive and invasive tests, such as spinal taps. Although blood tests are already used in clinics, they are often not covered by insurance and cost hundreds of dollars or more.
“Overall, this is a nice addition to the burgeoning literature, although not necessarily a game changer,” said Cliff Abraham, a professor of neuroscience and psychology at the University of Otago in New Zealand, who was not involved in the study.
The study authors collected data from patients with cognitive symptoms, whose average age was 74. About 23 percent of them had subjective cognitive decline, 44 percent mild cognitive impairment, and 33 percent dementia.
The authors measured the amount of p-tau217, a type of protein that accumulates and affects the brains of Alzheimer’s patients, and amyloid beta, another protein considered a biomarker for Alzheimer’s.
“It is clear, but not surprising, that the blood test provides better diagnostic accuracy than clinical evaluation, which only has access to indirect information about brain health, for example, cognitive tests,” Abraham said.
Alternatives to diagnosing Alzheimer’s include PET scans, which can cost $5,000 or more and are not reimbursed by Medicare except in trial periods, while lumbar punctures are invasive.
The study adds to evidence that diagnosing Alzheimer’s may soon be faster and easier. Faster, more accurate diagnoses could allow patients and their families to better prepare for medical bills, enroll in clinical trials or anticipate health care needs, the Centers for Disease Control and Prevention said.
Alzheimer’s is the most common form of dementia, affecting more than 6 million Americans. Although younger people can get Alzheimer’s, most sufferers are older adults. According to the CDC, the number of patients doubles every five years after age 65. Up to 14 million Americans may have Alzheimer’s by 2060.
The disease begins with mild memory loss, but can progress to patients being unable to carry on a conversation. It is one of the top 10 causes of death in the United States, with rising mortality rates. There is no cure, although there are medications that can slow the disease.