Abstract: Objective To explore the clinical significance of detection of serum calcitonin (PCT), amyloid protein A(SAA) and c-reactive protein (CRP) in leukaemia patients with fever and agranulocytosis after chemotherapy. Methods A retrospective analysis was conducted to evaluate the clinical data of 175 leukaemia patients with agranulocytosis and fever after chemotherapy from March 2016 to March 2018 in the Provincial Hospital Affiliated to Shandong University. Among them, 74 patients with positive bacterial culture were assigned to the infection group, and 67 healthy subjects from healthy check-up were selected as the control group. The differences of PCT, SAA and CRP between the two groups were analyzed, and the diagnostic efficacy of PCT, SAA and CRP was judged according to the ROC curve. Results The median levels of PCT, SAA and CRP in the infection group were significantly higher than those in the control group (P＞0.05). ROC curve analysis showed that PCT was the best in the diagnosis of bacterial infection, and its cutoff value, sensitivity and specificity were 0.285 μg/L, 86.76% and 80.40%, respectively. Conclusions The detection of serum PCT, SAA and CRP is of great significance in the early diagnosis of leukemia patients with agranulocytosis, infection and fever after chemotherapy. PCT has high specificity in determining the cause of fever.