Objective:

To analyze real-world HCP utilization of a high performing Alzheimer’s disease (AD) blood biomarker (BBM) test.

Background:

Little data exists regarding real-world HCP adoption practices of AD BBMs. Scientifically robust BBM tests stand to provide accurate and more equitable access to detecting brain amyloid pathology, a pathognomonic of AD. A blood test with an algorithm combining BBM ratios Abeta(Aβ)42/40 and %p-tau217 has demonstrated concordance with amyloid PET scan and CSF analysis in symptomatic patients. Results are reported as a numeric score (APS2) from 0-100, with ≥48 interpreted as positive, high likelihood for brain amyloid pathology. Clinical diagnostic laboratory examination of HCP ordering, patient demographics and test results may provide information about BBM utilization.

Design/Methods:

Data regarding 1000 consecutive patient samples analyzed with the PrecivityAD2 blood test,  C2N Diagnostics, LLC (St. Louis, MO) at start of Q2 (April 1), 2024, was retrospectively evaluated for age, self-reported sex and race/ethnicity, ICD-10 codes. Statistical analyses were performed to evaluate relationships between patient demographics and test results.

Results:

84.3% of patients were >65 years old at sample collection (median 75; range 46-98). 57.6% of patients reporting sex were female. 63.5% of patients had race/ethnicity data: 82.0% were White; 5.4% Black; 1.7% Asian; 10.9% Other/Unknown race; 4.7% indicated Hispanic ethnicity. 54.9% of APS2 results were positive, 45.1% negative; 87.2% of APS2 values were <30 or >60. Age positively correlated with APS2 values; there was no statistically significant correlation between patient sex, race/ethnicity and APS2 result. 83.8% HCP offices were metropolitan. Most common testing indications were MCI (32.4%), other amnesia (14.8%), AD unspecified (14.4%) and AD late-onset (8.6%).

Conclusions:

All patients received positive/negative results. Similar to previous studies, ~90% had APS2 values closer to  0 or 100 that were associated with higher (>93%) NPV and PPV. No other demographic factors besides age were helpful in distinguishing likelihood of amyloid plaques.