In the CLP model, serum IL1R2 rose within 4 h post-sepsis, peaked within 24 h, returned to baseline by day 3, and fell below normal by day 7.<h4>Conclusion</h4>Serum IL1R2 is a promising biomarker, offering a superior ability to correlate with disease severity and predict 28-day mortality. Here, IL1R2 is linked to Sepsis.