Researchers have produced a reliable blood test for the early stages of Alzheimer's disease. Early identification of Alzheimer's disease has long been a challenge for the medical community, and only in the past few years have inroads like this been made:
Researchers have announced the development of a blood test that leverages the body's immune response system to detect an early stage of Alzheimer's disease - referred to as the mild cognitive impairment (MCI) stage - with unparalleled accuracy. In a "proof of concept" study involving 236 subjects, the test demonstrated an overall accuracy, sensitivity and specificity rate of 100 percent in identifying subjects whose MCI was actually caused by an early stage of Alzheimer's disease. "About 60 percent of all MCI patients have MCI caused by an early stage of Alzheimer's disease. The remaining 40 percent of cases are caused by other factors, including vascular issues, drug side-effects and depression. To provide proper care, physicians need to know which cases of MCI are due to early Alzheimer's and which are not."
"Our results show that it is possible to use a small number of blood-borne autoantibodies to accurately diagnose early-stage Alzheimer's. These findings could eventually lead to the development of a simple, inexpensive and relatively noninvasive way to diagnose this devastating disease in its earliest stages. It is now generally believed that Alzheimer's-related changes begin in the brain at least a decade before the emergence of telltale symptoms. To the best of our knowledge, this is the first blood test using autoantibody biomarkers that can accurately detect Alzheimer's at an early point in the course of the disease when treatments are more likely to be beneficial - that is, before too much brain devastation has occurred."
For the study, the researchers analyzed blood samples from 236 subjects, including 50 MCI subjects with low levels of amyloid-beta 42 peptide in their cerebrospinal fluid. The latter is a reliable indicator of ongoing Alzheimer's pathology in the brain and predicts a likely rapid progression to Alzheimer's. Employing human protein microarrays, each containing 9,486 unique human proteins that are used as bait to attract blood-borne autoantibodies, the researchers identified the top 50 autoantibody biomarkers capable of detecting ongoing early-stage Alzheimer's pathology in patients with MCI. In multiple tests, the 50 biomarkers were 100 percent accurate in distinguishing patients with MCI due to Alzheimer's from healthy age- and gender-matched controls. Further testing of the selected MCI biomarker panel demonstrated similar high overall accuracy rates in differentiating patients with early Alzheimer's at the MCI stage from those with more advanced, mild-moderate Alzheimer's (98.7 percent), early-stage Parkinson's disease (98.0 percent), multiple sclerosis (100 percent) and breast cancer (100 percent).