Blood test for AD pathology demonstrates higher predictive accuracy than clinicians
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Key takeaways:
- The AD2 blood test was roughly 90% accurate at Alzheimer’s identification.
- Diagnoses of subjective cognitive decline, mild cognitive impairment and dementia arose from AD-positive pathology.
PHILADELPHIA — Utilization of a specialized blood test to detect Alzheimer’s-related pathology led to higher diagnostic accuracy compared to health care professionals’ identification, data show.
“An accurate blood test for Alzheimer’s disease could streamline the diagnostic work-up and treatment,” Sebastian Palmqvist, MD, PhD, of the Clinical Memory Research Unit at Lund University in Sweden, and colleagues wrote in their study, which was presented at the 2024 Alzheimer’s Association International Conference.
Palmqvist and fellow researchers sought to evaluate the accuracy of a blood test utilized in primary and secondary care to detect AD using predefined biomarker cutoffs and prospective analyses of plasma samples, compared with accuracy of identification by a physician in a clinical setting.
Their study included 1,213 individuals (treatment at memory clinics, n = 698; treatment at primary care, n = 515) with suspected early cognitive symptoms indicative of AD pathology, tested with the Precivity AD2 blood test. An Amyloid Probability Score-2 (APS2) was compiled, based upon combining %p-tau217 — a ratio of plasma phosphorylated-tau217 and non-phosphorylated-tau217 — as well as the ratio of both amyloid-beta 42/40. Plasma samples were submitted for biweekly analysis, with the main study outcome being amyloid status as determined by positive cerebrospinal fluid biomarkers indicative of AD.
In memory clinics, APS2 was approximately 90% accurate at identifying AD, with specialists operating at a 73% success rate. Similarly, in a primary care setting, APS2 also logged an approximate 90% accuracy rate with physicians registering 63% accuracy, Palmqvist and colleagues wrote.
The researchers additionally recorded a 51% AD pathology positivity rate in a primary care setting, within which 47% were diagnosed with mild cognitive impairment (MCI), 28% with dementia and 25% with subjective cognitive decline (SCD).
Data also showed a 49% accuracy rate in secondary care settings for AD pathology positivity, within which 43% were diagnosed with MCI, 36% had dementia and 21% had signs consistent with SCD.
“These were the results of blood samples that have been shipped biweekly for analysis from primary care units, which is similar to routine clinical practice,” Palmqvist said in a related release. “These results were especially impressive considering that older populations in primary care often have medical conditions that can influence or vary the concentrations of p-tau217.”
Reference:
Alzheimer’s disease blood tests could improve diagnosis in primary care, speed recruiting for research and reduce wait times. https://aaic.alz.org/releases-2024/blood-tests-alzheimers-biomarkers.asp. Published July 28, 2024. Accessed July 29, 2024.