A blood test approved by the U.S. Food and Drug Administration in May provides an inexpensive and noninvasive way to detect biomarkers of Alzheimer’s disease, vastly increasing opportunities for early detection and treatment.

Johns Hopkins neurologist Abhay Moghekar and his research team contributed important data and helped validate the test results for the new Alzheimer’s blood test.

“It makes things much easier for both patients and physicians,” says Moghekar. “New medications are now available to treat Alzheimer’s disease, but they are only effective if it is diagnosed early, and early diagnosis depends on having accurate biomarkers.”

The test, known as the pTau217/ß-Amyloid 1-42 Plasma Ratio, is FDA approved for patients who are 55 or older and have been medically assessed as experiencing cognitive decline. It was developed based on research completed at Johns Hopkins, Lund University and private companies.

Moghekar’s lab contributed important data and validated the test against the results from cerebrospinal fluid (CSF) biomarkers already approved by the FDA. “They pooled subjects from three studies to come up with this test,” he says. “We contributed many of the samples and did the testing of those samples here in our lab.”

The test is now being rolled out for primary care physicians and specialists to order through their electronic medical record systems, says Moghekar, with commercial diagnostic laboratories in the process of acquiring the necessary kits to process the results.

Moghekar says the test, which finds plasma biomarkers that indicate amyloid pathology, does not deliver a definitive diagnosis, but instead provides an amyloid range. Patients with scores over the high-end cutoff have more than a 90% likelihood of having Alzheimer’s disease, while patients below the low range almost certainly do not have it.

About 20% of those tested will fall in the intermediate category, he says, requiring additional testing from neurologists or gerontologists supported by supplemental PET scans and CSF testing to reach a confident diagnosis.

Before the Alzheimer’s disease blood test, amyloid buildup could be detected through PET scans of a patient’s brain, or by analyzing cerebrospinal fluid for signs of abnormal amyloid. Both techniques are invasive, expensive and require specialized equipment and personnel, Moghekar notes.