Objective:To explore the correlation between HRCT score and serum biomarkers for providing reference for early diagnosis and treatment of rheumatoid arthritis(RA)associated interstitial lung disease(ILD).Methods:A retrospective analysis of clinical and HRCT data of 284 RA patients was made.Among the 284 RA patients,132 cases were complicated with ILD(RA-ILD group),152 case were not(RA-N-ILD group).DAS28 and HRCT score evaluations were performed on the two groups.The serum biomarkers including ESR,CRP,rheumatoid factor(RF),anti-cyclic citrullinated peptide antibody(ACCPA),CEA,AFP,CA724,CA19-9,transferrin(FeD),fibrinogen(FIB)and D-dimer(DDI3)were collected.Logistic regression and ROC curve were used to analyze the correlation between HRCT score and indictors,and AUCs of each indicator were calculated.Results:There were statistical differences in gender,age,DAS28,ESR,RF,CEA,CA19-9,HRCT score between the two groups(all P<0.05),the patients in RA-ILD group were older and had higher levels of DAS28,RF,CEA,CA19-9 and HRCT score.Multivariate logistic regression analysis showed that DAS28,RF,CEA,CA19-9 could be used as independent predictors of RA-ILD.HRCT score was positively correlated with age,DAS28,ESR,CEA,CA19-9 and FIB(all P<0.05).Significant differences were also observed in HRCT score and imaging features between the two groups(all P<0.05).The AUCs for HRCT score,ESR,RF,CA19-9,CEA and DAS28 were 0.762,0.486,0.526,0.786,0.778 and 0.870,respectively,the corresponding sensitivities were 80.5%,73.2%,63.4%,75.6%,87.8%and 80.5%.The AUC and sensitivity of HRCT score combined with RF,CEA,CA19-9 were 0.947 and 88.3%,while those of HRCT score combined with ESR,DAS28,RF,tumor markers,coagulation markers were 0.959 and 82.9%.Conclusions:The combined application of HRCT score,RF,CEA and CA19-9 has the potential diagnostic value in RA patients who may have a risk of secondary ILD,and it can improve the early diagnostic accuracy and sensitivity of RA-ILD.