Blood Test Confirms Absence of Alzheimer’s Disease
Roche has announced that the FDA has cleared the Elecsys pTau181 test as the first blood-based biomarker for Alzheimer’s disease assessment. This test will aid in diagnosing Alzheimer’s and other cognitive decline causes in primary care settings.
New Blood Test for Alzheimer’s Disease
The Elecsys pTau181 test measures plasma levels of phosphorylated tau 181 (p-tau181). This biomarker is crucial in identifying amyloid plaque and tau aggregates associated with Alzheimer’s disease. The test is primarily designed for patients aged 55 and older who exhibit signs of cognitive decline, helping to rule out Alzheimer’s-related amyloid pathology.
Impact on Patient Care
The introduction of this blood test promises to enhance patient access to minimally invasive testing options. Roche stated that it enables primary care clinicians to direct suitable referrals to specialists. This focused approach allows neurologists to prioritize patients who truly require advanced diagnostic evaluations and treatments.
Clinical Study Support
- The clearance of the Elecsys pTau181 test was backed by a multicenter, non-interventional study.
- In this study, 312 participants reflected an early disease-stage, low-prevalence demographic typical of primary care.
- The test demonstrated a 97.9% negative predictive value for ruling out Alzheimer’s pathology.
Guidance from Alzheimer’s Association
Earlier this year, the Alzheimer’s Association released guidelines endorsing blood tests for Alzheimer’s biomarkers. These tests must achieve at least 90% sensitivity and 75% specificity for initial screenings. A negative result from these tests can rule out Alzheimer’s disease, while a positive result suggests further testing, such as PET scans or cerebrospinal fluid analysis.
Recent Developments in Alzheimer’s Diagnostics
In May, the FDA also approved the Lumipulse G pTau 217/β-Amyloid 1-42 Plasma Ratio test. This diagnostic is intended for individuals presenting symptoms of Alzheimer’s but only in specialized care settings. The trend toward early diagnosis is crucial, especially with new monoclonal antibodies like lecanemab (Leqembi) and donanemab (Kisunla) available for treating early symptomatic cases with verified amyloid pathology.
