[Diagnosis of bacterial and viral infection by HNL, SAA, PCT and CRP combined test].

The value of combined detection of neutrophil apolipoprotein (HNL), serum amyloid A (SAA), procalcitonin (PCT) and C-reactive protein (CRP) in the differential diagnosis of bacterial and viral infectious diseases. A retrospective study was conducted to collect the clinical data of infected patients and healthy people in the clinical department of Shaanxi Provincial People's Hospital from September to December in 2022. 100 patients with confirmed infection were divided into bacterial infection group (n=50) and virus infection group (n=50), and 50 healthy people were selected as control group (n=50). Fasting venous blood was collected at the initial stage of admission or on the day of physical examination. HNL was detected by double antibody sandwich method, SAA and CRP were detected by nephelometry, and PCT was detected by chemiluminescence method. The efficacy of infection markers in the differential diagnosis of bacterial infection and viral infection in infected patients was evaluated. The receiver operating characteristic (ROC) curve was used to evaluate the diagnostic efficacy of HNL, SAA, PCT and CRP in bacterial and viral infectious diseases; Logistic regression was used to analyze the influence of each index on the diagnostic efficiency. The results showed that the levels of HNL (126.60±33.32) ng/ml, PCT (28.02±11.37) ng/ml and CRP (36.13±14.37) mg/L in bacterial infection group were significantly higher than those of HNL (47.72±15.94) ng/ml, PCT (1.27±0.40) ng/ml, CRP (18.77±10.66) mg/L in virus group and HNL (38.21±12.53) ng/ml, PCT (0.38±0.12) ng/ml and CRP (4.13±1.07) mg/L in control group. The level of HNL increased most significantly (F=89.228, P<0.05). The area under ROC curve (AUC) from large to small was HNL+SAA+PCT+CRP (0.976), HNL (0.907), PCT (0.885), CRP (0.856), SAA (0.790), SAA/CRP (0.733). The level of SAA/CRP in virus infection group (94.05±3.75) was significantly higher than that in bacteria group (17.70±3.69) and control group (3.89±1.50) (F=84.005, P<0.05). The area under ROC curve (AUC) from large to small was HNL+SAA+PCT+CRP (0.986), SAA/CRP (0.956), SAA (0.878), HNL (0.768), CRP (0.742), PCT (0.730). In conclusion, HNL has the best auxiliary diagnostic efficacy in bacterial infection, followed by PCT; SAA/CRP has the best auxiliary diagnostic efficacy in viral infection, followed by SAA; the combined detection of serum HNL, SAA, PCT and CRP may be helpful for the differential diagnosis of bacterial and viral infections.