Abstract: Objective: To detect the levels of the hematology-related indexes in the tumor patients in intensive care unit(ICU), and to investgate their clinical application in the early diagnosis of bacterial infection in the tumor patients in ICU. Methods: The complete clinical materials of 256 tumor patients in ICU were analyzed retrospectively. According to the clinical bacterial infection standard, they were divided into infection group(67 cases) and non-infection group(189 cases), and according to the situation of death of patients, they were divided into survival group(193 cases) and death group(63 cases). The prothrombin time (PT), active part thrombin time (APTT) and D-Dimer(DD),the levels of procalcitonin (PCT) and the counts of white blood cell(WBC), neutrophile(NEU), lymphocyte(LYM) of the tumor patients in ICU in infection group and non-infection group were measured, and the neutrophile-to-lymphocyte ratio(NLR) was calculated. The sensitivities and specificities of each index in the early diagnosis of bacterial infection in the ICU tumor patients and PCT for predicting the mortality risk in the ICU tumor patients with early bacterial infection were assessed by receiver operating characteristic curve(ROC) and the area under the curve(AUC), and the their clinical values were explored. Results: Compared with non-infection group, the PT, APTT, DD, PCT level and NRL of the ICU tumor patients in infection group were significantly increased(P<0.05 or P<0.01).Compared with PCT<0.25 μg·L^-1 group, the DD and NRL levels of the ICU tumor patients with early bacterial infection in 0.25 μg·L^-1 ≤ PCT<2.00 μg·L^-1 group,2.00 μg·L^-1 ≤ PCT<10.00 μg·L^-1 group and PCT ≥ 10.00 μg·L^-1 group were significantly increased(P<0.05 or P<0.01); the PT and APTT levels of the ICU tumor patients with early bacterial infection in 2.00 μg·L^-1 ≤ PCT<10.00 μg·L^-1 group and PCT ≥ 10.00 μg·L^-1 group were significantly increased(P<0.05).The AUC, sensitivities and specificities of PT, APTT, DD, NLR and PCT in the diagnosis of early bacterial infection in the ICU tumor patients were 0.636, 60.8%, 59.1%; 0.622, 64.6%, 58.1%;0.672, 69.6%, 58.1%;0.752, 74.7%, 65.6%; 0.855, 70.9%, 83.9%; the differences were statistically significant (P<0.01).The PCT level of ICU tumor patients with early bacterial infection in death group was significantly higher than that in survival group (P<0.05).The AUC of PCT for predicting the mortality risk of ICU tumor patients with early bacterial infection was 0.803(95%CI:0.749-0.857), the cut-off value was 6.72 μg·L^-1, the sensitivity and specificity were 63.2% and 79.1%, respectively, and the differences were statistically significant (P<0.01). Conclusion: PT, APTT, DD, PCT and NLR can be used as the early diagnostic indicators of bacterial infection in the ICU tumor patients. The sensitivity of NLR and the specificity of PCT were the highest. PCT can be used as a predictor of the mortality risk in the ICU tumor patients with early bacterial infection.

Key words: coagulation function index, bacterial infection, intensive care unit, tumor