Objective: The aim of this study was to explore the value of serum amyloid A protein (SAA) and neutrophil-to-lymphocyte ratio (NLR) testing in the diagnosis and treatment of children with influenza A.
Methods: Specimens were collected from 85 children with influenza A, 85 children with a bacterial infection, and 86 healthy children. The levels of SAA and C-reactive protein (CRP) were measured, and routine blood tests were performed.
Results: The levels of SAA and CRP in the bacterial infection group were significantly higher than those in the influenza A group, and the levels in the influenza A group were higher than those in the healthy children. The NLR level in the influenza A group was not different from that in the bacterial infection group, but the NLR levels in the influenza A group and the bacterial infection group were higher than that in the healthy controls. The number of white blood cell (WBC) in the influenza A group was not different from that in healthy children, while the WBC counts in the control and bacterial infection groups were higher than that in the influenza A group. The distribution width of red blood cells in the bacterial infection group was higher than that in healthy controls. The receiver operating characteristic curve analysis showed that the area under the curve for the diagnoses of influenza A for SAA, NLR, and CRP was 0.806, 0.768, and 0.699, respectively. The sensitivity, specificity, positive predictive value, negative predictive value, and accuracy of SAA/NLR (SAA and NLR in the series) were 68.24%/76.47% (57.65%), 84.88%/72.09% (96.76%), 81.69%/73.03% (96.08%), 73.00%/75.61% (70.00%), and 76.61%/74.27% (77.78%), respectively.
Conclusion: In the early diagnosis of children with influenza A, the values of SAA and NLR are high. Thus, they could be used for monitoring and efficacy evaluation during the course of the disease.
Keywords: influenza A, serum amyloid protein; SAA, neutrophil/lymphocyte ratio, white blood cell, C-reactive protein