Major Research Findings Highlight Effectiveness of the PrecivityAD™ Blood Test That Clinicians Use to Aid in Alzheimer’s Disease Diagnosis

ST. LOUIS--(BUSINESS WIRE)-- Four separate research reports presented at premier Alzheimer’s disease and aging conferences add to the increasing set of details about the accuracy and clinical usefulness of the PrecivityAD™ blood test from C2N Diagnostics. The PrecivityAD™ test is a breakthrough blood test intended for use in patients with cognitive impairment. The test helps physicians determine the presence or absence of amyloid plaques in the brain, a hallmark sign of Alzheimer’s disease (AD).

Blood Test Will be Used for Prescreen in Landmark Prevention Study; Other Research Highlights Its Accuracy

The AHEAD Study, a clinical trial occurring at 75 research centers aimed at preventing memory loss, announced yesterday that it will use the PrecivityAD™ blood test in further studies.

Data presented from the AHEAD investigators at the international Clinical Trials on Alzheimer’s Disease (CTAD) conference in Boston showed PrecivityAD™ is 81% accurate (with an area under the receiver operating characteristic curve (AUROC) of 0.87) in predicting the level of amyloid on a PET scan. A PET scan is the traditional method to determine build-up of amyloid plaques in the brain among people who do not show symptoms of Alzheimer’s disease.

In a separate development at CTAD, Suzanne Schindler, M.D., Ph.D., with Washington University School of Medicine, presented data from 1,085 individuals that showed the PrecivityAD™ blood test was highly concordant with CSF biomarkers and amyloid PET status in both cognitively normal (74% of those studied) and cognitively impaired (26%) individuals. The AUROC for the PrecivityAD™ blood test with CSF biomarker status was 0.92. Dr. Schindler also explained that the PrecivityAD™ blood test was very sensitive and “false positives” were highly likely to convert to positive by CSF biomarkers (with a 13-fold higher risk over an average follow-up period of 7.3 years) or amyloid PET (with a 9-fold higher risk over an average follow-up period over 6.2 yrs).

“Prediction of Brain Amyloid Pathology Using Plasma Aβ42/40 Ratio Measured Using PrecivityAD™ Test in the MissionAD Study Samples” also delivered important findings. Researchers report the PrecivityAD™ blood test that measures the Aβ42/40 ratio shows potential for use as a screening tool to enrich for individuals considered likely to be brain amyloid positive. They stated that blood tests, including this one, may detect brain amyloid earlier than PET imaging. This conclusion is based on evaluating PrecivityAD™ blood test results against both PET visual read and centiloid (CL).

Finding: Patients Receive More Precise Diagnosis With Blood Test

At the Gerontological Society of America (GSA) Annual Meeting, research was shared that involved asking physicians ordering the PrecivityAD™ blood test to evaluate the following for each patient before and after the blood test was given:

  • Likelihood of AD (% estimates);
  • Medication prescribing plan (anti-AD drugs); and
  • Additional advanced diagnostic testing ordering (e.g., PET scan, Cerebrospinal fluid analysis).

Each of the 31 patients in the project had symptoms of cognitive impairment. The team found that the physician-rated average likelihood of AD for the patients dropped from 64% pre-test to 41% post-test (p=0.0011). This 36% relative reduction was judged by the investigators to be clinically relevant and statistically significant.

For instance, one physician reported a patient in his 70s had an 80% AD likelihood pre-test and only a 20% likelihood after a low Amyloid Probability Score (APS) of 3, the test output value. This result led the doctor to stop a plan to prescribe an anti-AD drug.

Mark Monane, M.D., M.B.A, a geriatrics specialist, C2N consultant and one of the researchers, states that “This project highlights that there’s an important unmet need for timely, non-invasive and low-burden evaluation of patients presenting with cognitive impairment.”

Monane and his colleagues found that the pre-test likelihood was remarkably similar across all APS groups (61%–71%). He says this finding suggests that physicians need new, improved techniques for evaluating the likelihood of brain amyloidosis in their patients. However, after the PrecivityAD™ blood test was performed, the physicians’ estimate of likelihood of AD dropped from 61% to 15% in the low APS group and rose from 71% to 98% in the high APS group.

Joining Monane in the project work, titled “Early Clinical Utility Data of a Blood Biomarker Test in the Evaluation of Mild Cognitive Impairment,” was Jonathan D. Drake, M.D., of Brown University and B. Joy Snider, M.D., Ph.D., of Washington University School of Medicine in St. Louis.

Joel Braunstein, M.D., CEO of C2N Diagnostics, says, “These different research studies bolster the growing body of evidence that advance the medical community’s understanding of the effectiveness of the PrecivityAD™ blood test. The PrecivityAD™ blood test using mass spectrometry has shown robust analytic validity and clinical validity in the detection of amyloid deposits in the brain. The MissionAD data is consistent with what the AHEAD investigators reported; the key difference is that individuals in AHEAD are pre-symptomatic while those in MissionAD had mild cognitive impairment, early AD. These are important implications for lowering costs and time of enrollment for both prevention and treatment studies.”

Early Diagnosis Benefits

There are important benefits for a person receiving an early AD diagnosis, in addition to helping clinicians rule out AD pathology and that allows them to look for other explanations of cognitive loss.

These benefits to patients include the fact they could:

  • Receive appropriate medical attention;
  • Start lifestyle adjustments; and
  • Become eligible for clinical research.

Further details are available at

About C2N Diagnostics, LLC

C2N Diagnostics is a specialty diagnostics company with a vision to bring Clarity Through Innovation™. C2N strives to provide exceptional laboratory services and products in the field of brain health. C2N’s biomarker services and products are used for: clinical decision making to improve patient care, including diagnosis and treatment monitoring; maximizing the quality and efficiency of clinical trials that test novel treatments for neurodegeneration; and providing innovative tools to help healthcare researchers better understand novel mechanisms of disease, identify new treatment targets, and conduct important epidemiologic studies to improve global public health. For more information visit


Adam Shapiro


Source: C2N Diagnostics, LLC

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