Common laboratory blood test immune panel markers are useful for grading ulcerative colitis endoscopic severity

BACKGROUND: At present, many indicators reflect the clinical disease activity of ulcerative colitis (UC). However, commonly used inflammatory markers do not show good utility for indicating endoscopic disease activity. The purpose of this study was to evaluate high sensitivity C-reactive protein (hs-CRP), C-reactive protein to albumin ratio (CAR), inflammatory markers, and complete blood count (CBC) related parameters in patients with UC as simple, non-invasive, and independent markers of endoscopic activity (EA). METHODS: We retrospectively collected extensive data from the hospital medical records of 386 patients who presented with UC to the First Affiliated Hospital of Xinjiang Medical University (Urumqi, China) from 2018 to 2022 January. The Mayo endoscopic score (MES) was used to evaluate endoscopic disease activity. All included patients were defined as the MES-All group; those with extensive colitis (E3) were defined as the MES-E3 group. Demographics, laboratory parameters, endoscopic results, the extent of disease, and drug history were recorded and analyzed. RESULTS: For patients in the MES-All or MES-E3 group, hs-CRP, CAR, neutrophil to lymphocyte ratio (NLR), and platelet to lymphocyte ratio (PLR) were significantly higher in EA UC patients than in those with mucosal healing. The mean platelet volume (MPV) and lymphocyte to monocyte ratio were significantly lower in active disease than in the patient’s remission (p < 0.001). ROC analysis showed that in the MES-All and MES-E3 groups, the cutoff values of hs-CRP activity under endoscopy were 5.32 mg/L (AUC 0.850, sensitivity 77.6%, specificity 81.9%) and 5.16 mg/L (AUC 0.902, sensitivity 86.9%, specificity 85.4%) respectively, and the cutoff values of CAR were 0.14 (AUC 0.853, sensitivity 76.8%, specificity 84.8%) and 0.18 (AUC 0.904, sensitivity 81.8%, specificity 89.6%) respectively. Multivariate logistic regression analysis showed that hs-CRP, CAR, NLR, and PLR identified UC EA, while decreased MPV reflected inflammatory activity in the UC mucosa. CONCLUSION: Especially in patients with extensive colitis, hs-CRP and CAR are closely related to EA and show a higher diagnostic value compared to the related CBC parameters. The aforementioned indicators are simple and non-invasive independent markers that reflect the EA in UC. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1186/s12876-022-02634-x.