Observed Clinical and Operational Factors Are Associated with Biomarker Test Utilization in Respiratory Virus RT-PCR Testing: A Real-World Analysis of Inflammatory, Cardiac, and Thrombotic Biomarkers

Background/Objectives: Routinely collected biomarker data are generated through selective testing. We examined associations of observed clinical and operational factors with biomarker availability and explored the incremental discrimination provided by biomarker concentrations for respiratory viral RT-PCR positivity.

Methods

This retrospective study included 7726 testing episodes for 13 respiratory viral targets from July 2020 to March 2025. Seven biomarkers were linked using a ±24-h reporting-time window. Models included age, sex, requesting department, operational time, calendar month, and year. Additional analyses included inverse probability weighting (IPW), weight and overlap diagnostics, and five repetitions of five-fold cross-validation.