An apparent limitation of our study is our failure to obtainserological confirmation of the diagnosis of DI in nearly one-fifthof our patients. The lack of IgM anti-dengue antibodies in thesepatients was possibly related to testing during an early phase ofillness. It is known that anti-dengue virus antibodies may not bepresent during the initial days of illness.22 However, even in ourseronegative patients, the presence of fever and thrombocytopeniain the epidemiological setting of an outbreak makes the diagnosisfairly certain.