Diagnostic value of serum amyloid A, procalcitonin and C-reactive protein for neonatal infectious pneumonia

ObjectiveTo investigate the application value of serum amyloid A (SAA), procalcitonin (PCT) and C-reactive protein (CRP) in the diagnosis of neonatal infectious pneumonia.

MethodsA series of 74 neonates diagnosed with infectious pneumonia and 98 neonates without infection in neonatology department of Yongkang Maternity and Children′s Hospital from June 2018 to May 2019 were enrolled in this study.Their serum levels of SAA, PCT and CRP were measured by electrochemiluminescence and immunoturbidimetry.Receiver operating characteristic curve was used to predict the diagnostic efficiency of the three biomarkers.

ResultsThe levels of SAA, PCT, CRP and SAA/CRP ratio in the bacterial infection group were all higher than those in the healthy control group (P < 0.01).There was no statistically significant difference in PCT level (0.09 ng/mL vs 0.12 ng/mL) between the viral infection group and the healthy control group (Z=-0.604,P=0.546), while the levels of SAA, CRP and SAA/CRP ratio in the viral infection group were all higher than those in the healthy control group (P < 0.01).The ROC curve showed that SAA had the largest area under the curve (AUC) in the diagnosis of both bacterial and viral pneumonia in neonates (0.971 and 0.858), indicating the highest diagnostic efficiency among the four indicators.SAA/CRP ratio had the best sensitivity (97.2%) and PCT the best specificity (100%) when the four indicators were used for the diagnosis of neonatal bacterial infectious pneumonia.The SAA/CRP ratio had the best sensitivity (87.5%) and CRP the best specificity (96.9%) when used in the diagnosis of neonatal viral pneumonia.

ConclusionAs a new infection biomarker, SAA can provide useful information for the diagnosis of neonatal infectious pneumonia.SAA, PCT, CRP and SAA/CRP ratio are all useful.SAA/CRP ratio can be used for disease screening and those biomarkers with high specificity can be used for disease confirming.The combined detections can improve the sensitivity and specificity of diagnosis, which is useful for clinical promotion.