Researchers published a four‑gene blood signature in Nature Communications that accurately excludes bacterial causes of lower respiratory tract infections (LRTIs). The study validated the minimal transcriptomic panel across clinical cohorts and demonstrated performance that could reduce unnecessary antibiotic prescribing at the point of care. LRTI denotes infections of the lower airways; a rapid blood‑based rule‑out could change emergency‑department and primary‑care decision pathways and has implications for antimicrobial stewardship.