Real-world patterns of Alzheimer’s disease biomarker testing: Insights from a large-scale clinical dataset (Overview, 2026)

A large-scale clinical dataset from Labcorp (over 234,000 patients) reveals heterogeneous, real-world patterns of Alzheimer’s disease (AD) biomarker testing, including frequent use of ATN profile and p‑Tau217 as initial tests, non-linear diagnostic pathways, and substantial co‑testing with metabolic and endocrine labs within 90 days of AD biomarker orders.

Analyses of first biomarker orders show that starting with the ATN profile leads to different downstream testing patterns than starting with p‑Tau217, highlighting variability in clinical decision‑making compared with standardized research protocols.

The dataset also captures longitudinal biomarker changes in patients with repeat testing, and illustrates how co‑testing (e.g., A1c, TSH, Vitamin B12, Vitamin D) reflects guideline‑informed workup behavior but rarely follows a rigid, linear sequence.

Overall, this work demonstrates the value of large‑scale real‑world data for understanding AD care pathways, co‑testing, repeat testing behavior, and adherence to evolving diagnostic guidance in routine clinical practice.