Abstract: Objective：To evaluate the effect of the viral load on the red blood cell parameters in chro-nic hepatitis B patients and its clinical significance. Methods: In the study, 373 chronic hepatitis B patients were recruited, including 123 alanine transaminase (ALT) normal patients (ALT<40 U/L),128 ALT greater than or equal to the upper limit of normal, and less than 2 times higher than the upper limit of normal patients(40 U/L ≤ALT<80 U/L), and 122 ALT greater than or equal to 2 times higher than the upper limit of normal patients (ALT≥80 U/L). The blood routine parameters were measured by automatic blood cell counter. The liver function parameters were measured by automatic biochemical analyzer, the hepatitis B virus loads were measured by quantitative PCR analyzer and the results were analyzed by covariance analysis. Results: In the ALT normal chronic hepatitis B patients group, the viral load had minor effects on the red blood cell parameters.But in the ALT abnormal chronic hepatitis B patients group, the viral load had a significant effect on the red blood cell parameters, and the effect was most manifest in the ALT≥ double upper limit of normal group. The specific performance was that with the viral load increasing,   the red blood cell ［low copies group (4.10±0.67)×1012/L，medium copies group (3.92±0.69)×1012/L，high copies group (3.54±0.90)×1012/L］, the hemoglobin［low co-pies group (129.66±21.12 ) g/L, medium copies group (126.23±23.38) g/L, high copies group (112.98±27.77) g/L］, the hematocrit (low copies group 37.66±5.68, medium copies group 37.03±6.03, high copies group 33.34±8.15) decreased（P=0.006，0.007，0.010)，the mean corpuscular volume ［low copies group (92.17±6.53) fL, medium copies group (94.85±7.95) fL, high copies group (101.63±11.33) fL］, the mean corpuscular hemoglobin ［low copies group (31.70±2.22) pg, medium copies group (33.11±3.62) pg, high copies group (34.65±3.13) pg］, the mean corpuscular hemoglobin concentration ［low copies group (344.28±17.17) g/L, medium copies group (351.33±16.90) g/L, high copies group (358.12±15.67) g/L］, and the red blood cell distribution widthstandard deviation ［low copies group (52.49±9.04) fL, medium copies group (56.96±7.19) fL, high copies group (61.23±7.23) fL］ increased（P=0.000，0.000，0.002，0.000). Conclusion: Observing the effect of the viral load on the red blood cell parameters in chronic hepatitis B patients can reflect the effect of hepatitis B virus on the immune response and liver function in the different pathological stages, providing theoretical support for the clinical antiviral treatment.

Key words: Hepatitis B, chronic, Viral load, Erythrocytes