C-reactive protein in children with dengue fever in Vietnam

Precise diagnosis of the severity of dengue fever (DF) and its timely treatment reduce its mortality, but the sensitivity of clinical presentations is low for the classification of severity. Research on biomarkers is ongoing, and some studies in adults have shown the utility of C reactive protein (CRP) in the early diagnosis of dengue severity. However, the role of CRP in children with DF is still unknown. The aim of this study was to determine the value of CRP in distinguishing between DF and severe DF. A cross-sectional study was conducted from May 2016 to April 2017 at Children's Hospital 1 in Ho Chi Minh City, Vietnam. Serum CRP was tested on days 4 and 5 of the disease. Laboratory tests for DF were based on either a positivity for non-structured glycoprotein-1 antigen (NS1Ag) or enzyme-linked immunosorbent assay (ELISA) for immunoglobulin (Ig) M in acute phase serum. Among 270 patients, 29.6% had DF, 26.7% had DF with warning signs, and 43.7% had severe DF. The CRP level was measured in 123 patients on day 4 and 147 patients on day 5 of the illness. The median CRP level for DF was 2.4 mg/L, for DF with warning signs was 6.7 mg/L, and for severe DF was 7.3 mg/L. The CRP level was higher on day 4 than on day 5. The CRP level showed a statistically significant difference between the group with circulatory dysfunctions (p=0.02) or liver dysfunction (p= 0.04) and the other patients. The CRP cut-off point on day 4 that distinguished DF and severe DF was 5.8 mg/L and the area under the receiver operating characteristic curve (AUC) was 0.89, with a sensitivity of 82.9% and specificity of 80%. The CRP concentration in the early stage of illness may, therefore, help to distinguish between DF and severe DF.