血常规、血清SAA、PCT在发热患者细菌感染诊断中的应用

Application of Blood Routine, Serum SAA and PCT in the Diagnosis of Bacterial Infection in Patients with Fever

目的:探究血常规、血清淀粉样蛋白A(SAA)、降钙素原(PCT)在发热患者细菌感染诊断中的应用。方法:选取2019年5月-2022年5月于宁德市蕉城区医院住院期间出现感染性发热患者128例,根据是否发生细菌感染分为细菌组85例,非细菌组43例,另选择同期来院体检的健康人50例作为健康组。采用全自动五分类血细胞分析仪检测白细胞总数(WBC)及中性粒细胞百分率(NEUT),采用特定蛋白分析仪检测SAA水平,采用电化学发光免疫分析(ECLIA)检测PCT水平。后对WBC、NEUT、SAA及PCT诊断细菌性感染的价值进行受试者工作特征曲线(ROC)分析。结果:85例细菌感染的患者共分离出病原菌80株,其中革兰阴性菌共46株(57.50%),革兰阳性菌共34株(42.50%)。细菌组和非细菌组WBC、NEUT、SAA及PCT水平显著高于健康组,差异均有统计学意义(P<0.05),细菌组WBC、NEUT、PCT水平均显著高于非细菌组,差异均有统计学意义(P<0.05),非细菌组SAA水平显著高于细菌组,差异有统计学意义(P<0.05)。细菌组中WBC、NEUT、SAA及PCT阳性率分别为92.94%、91.76%、94.12%及96.47%,其中PCT阳性率较高;非细菌组中WBC、NEUT、SAA及PCT阳性率分别为18.60%、27.91%、100.00%及9.30%,两组WBC、NEUT及PCT阳性率对比,差异均有统计学意义(P<0.05)。单独诊断时,PCT表达截断值为0.63 ng/mL诊断细菌性感染效能最高,曲线下面积0.913,敏感度92.94%,特异度90.70%;SAA表达截断值为68.79 mg/L诊断细菌性感染效能次之,曲线下面积0.862,敏感度89.41%,特异度88.37%。结论:细菌性感染的WBC、NEUT及PCT水平较非细菌性感染更高,而SAA水平较非细菌性感染更低,WBC、NEUT、PCT及SAA水平对发热患者是否存在细菌感染均有一定诊断价值,其中又以PCT及SAA水平对细菌性感染诊断价值较高。

Objective: To explore the application of blood routine, serum amyloid A(SAA) and procalcitonin(PCT) in the diagnosis of bacterial infections in patients with fever. Method: A total of 128 patients with infectious fever during hospitalization in Ningde City Jiaocheng District Hospital were selected from May 2019 to May 2022. According to whether bacterial infection occurred, the patients were divided into 85 cases in bacterial group and 43 cases in non-bacterial group. In addition, 50 healthy people who came to the hospital for physical examination during the same period were regarded as healthy group. The total count of white blood cells(WBC) and the percentage of neutrophil(NEUT) were detected by automatic five-category blood cell analyzer, and the SAA level was measured by the colloidal gold method and the PCT level was detected by electrochemiluminescence immunoassay(ECLIA). The value of WBC, MEUT, SAA and PCT in the diagnosis of bacterial infection were analyzed by receiver operating characteristic curve(ROC). Result: Eighty strains of pathogenic bacteria were isolated from 85 patients with bacterial infection, including 46 strains(57.50%) of Gram-negative bacteria and 34strains(42.50%) of Gram-positive bacteria. The levels of WBC, NEUT, SAA and PCT in bacterial group and nonbacterial group were significantly higher than those in healthy group(P<0.05), and the levels of WBC, NEUT and PCT in bacterial group were significantly higher than those in non-bacterial group(P<0.05), and the SAA level in non-bacterial group was significantly higher than that in bacterial group(P<0.05). In bacterial group, the positive rates of WBC, NEUT, SAA and PCT were 92.94%, 91.76%, 94.12% and 96.47% respectively, and the positive rate of PCT was higher. In non-bacterial group, the positive rates of WBC, NEUT, SAA and PCT were 18.60%, 27.91%,100.00% and 9.30% respectively, and the differences in the positive rates of WBC, NEUT and PCT between the two groups were statistically significant(P<0.05). When the cut-off value of PCT expression was 0.63 ng/mL, it had the highest diagnostic efficiency on bacterial infection, and its area under the curve, sensitivity and specificity were 0.913,92.94% and 90.70%. When the cutoff value of SAA expression was 68.79 mg/L, it had secondary high efficiency in the diagnosis of bacterial infection, with the area under the curve of 0.862, sensitivity of 89.41% and specificity of 88.37%. Conclusion: The levels of WBC, NEUT and PCT of patients with bacterial infection are higher than those of patients without bacterial infection, while the level of SAA is lower than that of patients without bacterial infection.The levels of WBC, NEUT, PCT and SAA are of certain diagnostic value on bacterial infection in patients with fever,and PCT and SAA are of higher diagnostic value on bacterial infection.