Objective To investigate the diagnostic value of endoscopic sign of light blue crest(LBC)capsuling papillary lesion(LCPL)for high-risk intestinal metaplasia(IM).Methods A total of 314 patients(352 biopsy specimens)who underwent endoscopic examination and biopsy in Department of Gastroenterology of Army Medical Center of PLA from January 2021 to June 2023 were recruited,and HE and HID-AB staining(the golden standard of high-risk IM)were apllied to detect the histological types and IM types.The samples were subsequently divided into chronic inflammation group,low-risk IM group,high-risk IM group,well-differentiated intestinal-type gastric cancer group,and poorly-differentiated intestinal-type gastric cancer group.The positive rate of LCPL in each group and its diagnostic efficacy were analyzed based on endoscopic images of the biopsy sites.Logistic regression analysis was used to investigate the relationship between LCPL sign and high-risk IM,as well as the clinical and pathological features associated with LCPL sign.Receiver operating characteristic(ROC)curve was plotted to evaluate the diagnostic efficacy of LCPL for high-risk IM,using indicators such as sensitivity,specificity,Youden index and area under the curve(AUC).Results The positive rate of the LCPL sign in high-risk IM group was 75.70%,significantly higher than that of the other groups(all P<0.001).Logistic regression analysis showed that LCPL sign was significantly correlated with high-risk IM(OR=30.286,95%CI:13.528～67.804,P<0.001).When the sign was employed in diagnosing high-risk IM,the sensitivity was 69.84%,the specificity was 93.75%,the Youden's index was 0.636,and the AUC value was 0.818(95%CI:0.773～0.857).Besides sensitivity,all above parameters of LCPL sign showed significantly better diagnostic efficacy than those of traditional LBC sign,which is used as a sign for diagnosing IM(P<0.001).Moreover,recognition of LCPL sign was not easily affected by age(OR=1.130,95%CI:0.709～1.800,P=0.607),lesion site(Angular incisure:OR=2.360,95%CI:0.732～7.613,P=0.151;Autrum:OR=2.257,95%CI:0.756～6.744,P=0.145),and presence of peptic ulcers(OR=1.085,95%CI:0.208～5.652,P=0.923).Significantly,94.12%of positive and 66.94%of negative LCPL signs could be rapidly recognized within 3 s(OR=4.536,95%CI:1.372～14.997,P=0.013).Conclusion LCPL sign shows high efficacy and potential clinical application value for high-risk IM in gastric mucosa of endoscopic diagnosis.