Objective To explore the expression and diagnostic value of serum bilirubin,C-reactive protein (CRP),and apolipoprotein A1(APO-A1)levels in patients with diabetic foot(DF).Methods A total of 96 diabetic patients admitted to the Fourth Affiliated Hospital of Nanchang University from February 2021 to February 2022 were selected as the research objects.According to whether they were complicated with DF,the included subjects were divided into DF group (n=48)and non-DF group (n=48).Peripheral venous blood was collected from the patients,and the expression levels of total bilirubin(TBil),direct bilirubin (DBil),indirect bilirubin (IBil),CRP and APO-A1 were detected and compared between the two groups.Pearson was used to analyze the correlation between the severity of DF and TBil,IBil,CRP,APO-A1.The receiver operating characteristic(ROC)curve was used to analyze the diagnostic value of different indexes for DF.Results There was no significant difference in DBil level between the two groups (P＞0.05).The CRP level of DF group was higher than that of non-DF group,and the difference was statistically significant (P＜0.05).The levels of TBil,IBil and APO-A1 in DF group were lower than those in non-DF group,and the differences were statistically significant(P＜0.05).Pearson analysis showed that the severity of DF was positively correlated with TBil,IBil,CRP,APO-A1(r=0.302,0.302,0.982,0.469,P＜0.05).The sensitivity and specificity of TBil in diagnosing DF were 100.00%and 83.10%,respectively.The sensitivity and specificity of IBil in diagnosing DF were 83.30% and 60.40%,respectively.The sensitivity and specificity of CRP in the diagnosis of DF were 97.90%and 100.00%,respectively.The sensitivity and specificity of APO-A1 in diagnosing DF were 85.40%and 27.10%,respectively.The sensitivity,specificity and area under the curve of TBil,IBil,CRP and APO-A1 in the combined diagnosis of DF were 100.00%,95.23% and 0.998,respectively.The sensitivity of combined detection of TBil,IBil,CRP and APO-A1 indicators was higher than that of IBil and APO-A1 indicators alone,and the specificity was higher than that of IBil,APO-A1 and TBil indicators alone,the differences were statistically significant(P＜0.05).Conclusion Bilirubin and CRP have high expression levels in DF patients,while APO-A1 expression level is low.The combined detection of bilirubin,CRP and APO-A1 has high diagnostic value in DF patients