Abstract: AIM:To establish a simple model consisting of the routine laboratory variables to predict both minimal fibrosis and cirrhosis in chronic hepatitis B virus (HBV)-infected patients.METHODS:We retrospectively investigated 114 chronic HBV-infected patients who underwent liver biopsy in two different hospitals.Thirteen parameters were analyzed by step-wise regression analysis and correlation analysis.A new fibrosis index [globulin/platelet (GP) model] was developed,including globulin (GLOB) and platelet count (PLT).GP model =GLOB (g/mL) x 100/PLT (x 109/L).We evaluated the receiver operating characteristics analysis used to predict minimal fibrosis and compared six other available models.RESULTS:Thirteen clinical biochemical and hematological variables [sex,age,PLT,alanine aminotransferase,aspartate aminotransferase (AST),albumin,GLOB,total bilirubin (T.bil),direct bilirubin (D.bil),glutamyl transferase,alkaline phosphatase,HBV DNA and prothrombin time (PT)] were analyzed according to three stages of liver fibrosis (F0-F1,F2-F3 and F4).Bivariate Spearman's rank correlation analysis showed that six variables,including age,PLT,T.bil,D.bil,GLOB and PT,were correlated with the three fibrosis stages (FS).Correlation coefficients were 0.23,-0.412,0.208,0.220,0.314 and 0.212; and P value was 0.014,< 0.001,0.026,0.018,0.001 and 0.024,respectively.Univariate analysis revealed that only PLT and GLOB were significantly different in the three FS (PLT:F =11.772,P <0.001; GLOB:F =6.612,P =0.002).Step-wise multiple regression analysis showed that PLT and GLOB were also independently correlated with FS (R2 =0.237).By Spearman's rank correlation analysis,GP model was significantly correlated with the three FS (r =0.466,P < 0.001).The median values in F0-F1,F2-F3 and F4 were 1.461,1.720 and 2.634.Compared with the six available models (fibrosis index,AST-platelet ratio,FIB-4,fibrosis-cirrhosis index and age-AST model and age-PLT ratio),GP model showed a highest correlation coefficient.The sensitivity and positive predictive value at a cutoff value < 1.68 for predicting minimal fibrosis F0-F1 were 72.4% and 71.2%,respectively.The specificity and negative predictive value at a cutoff value < 2.53 for the prediction of cirrhosis were 84.5% and 96.7%.The area under the curve (AUC) of GP model for predicting minimal fibrosis and cirrhosis was 0.762 [95% confidence interval (CI):0.676-0.848] and 0.781 (95% CI:0.638-0.924).Although the differences were not statistically significant between GP model and the other models (P all > 0.05),the AUC of GP model was the largest among the seven models.CONCLUSION:By establishing a simple model using available laboratory variables,chronic HBV-infected patients with minimal fibrosis and cirrhosis can be diagnosed accurately,and the clinical application of this model may reduce the need for liver biopsy in HBVinfected patients.