CEACAM5 and cholecystolithiasis: The addition of cholecystolithiasis, fever and CEA > 5 ng/ml to SUVR allowed a significant reclassification with IDI = 0.369 (95% CI: 0.246–0.491, P < 0.001) and categorical NRI = 0.426 (95% CI: 0.160–0.692, P < 0.001) compared to SUVR alone.