Aspartate aminotransferase to platelet ratio index (APRI) for differentiation of primary and secondary infection by dengue virus

ABSTRACT INTRODUCTION: Dengue virus (DENV) infection has been considered a major public health problem in tropical countries. The unavailability of serologic testing in public health centers might adversely impact patients' outcome. OBJECTIVE: This study aimed to evaluate the accuracy of mean platelet volume (MPV) and aspartate aminotransferase (AST) to platelet ratio index (APRI) as laboratory markers of DENV infection that could be used to differentiate primary and secondary infections. METHODS: We assessed laboratory results from 503 patients with positive rapid test for DENV infection. RESULTS: Severe thrombocytopenia and increased liver involvement were observed in patients with DENV heterotypic secondary infection. Our data suggest that APRI was able to distinguish patients with primary and secondary infection (p = 0.006) with a relevant sensitivity (75%), specificity (76%) and a cut-off of 1.06. A total of 80 out of 105 (76%) patients with primary DENV infection had APRI ≤ 1.06, and 12 (75%) with secondary DENV infection had APRI > 1.06. On the other hand, MPV did not show significance in the differentiation of types of infection, coming up with poor area under the receiver operating characteristic (ROC) curve (0.61). CONCLUSION: APRI seems to be a powerful tool for early identification of DENV secondary infection cases in health centers.