Abstract: Objective: To explore a simplified method of coagulation test for the individuals with erythrocytosis. Methods: The anticoagulants, blood volume and fixed blood collecting volume were adjusted by the formula: anticoagulants (mL)=(100-HCT×100)×blood (mL)×0.001 85. A total of 124 blood samples for coagulation testing in which the calcium (Ca²⁺) interval was designated and hematocrit (HCT) was more than 55% were tested with calibrated anticoagulants, adjusted blood volume and fixed blood collection volume [anticoagulant(mL)/0.055 5]. The results of plasma prothrombin time (PT), international standardization ratio (INR) and activated partial thromboplastin time (APTT) before and after adjustment were compared. The results of the samples from 3 groups after adjustment were also compared. The relationship of HCT with unadjusted PT and APTT were simultaneously observed. Results: The unadjusted results of PT, INR and APTT were significantly higher than those after anticoagulants adjustment (27.52±16.37 vs 12.49±1.35, 2.31±1.47 vs 0.99±0.11 and 50.09±13.32 vs 33.37±5.05) with statistically significant difference in paired comparison (P＜0.05). No statistical difference was found in the comparison of the results for PT, INR and APTT after adjustment within the 3 groups (PT: 12.49±1.35 vs 12.84±1.54 vs 12.82±1.76, INR:0.99±0.11 vs 1.02±0.13 vs 1.02±0.15, APTT: 33.37±5.05 vs 33.49±5.09 vs 32.83±5.06) (P>0.05). HCT values of the patients were positively correlated with unadjusted PT (r=0.461, P＜0.05) and APTT (r=0.571, P＜0.05). Conclusion: The coagulation test of the individuals with erythrocytosis may use to adjust the blood volume and the fixed blood collection volume provided calcium concentration in reference interval.