A study was undertaken to analyze the usefulness of radiographic and ultrasonographic findings and area specific hematocrit cut off values in Dengue Hemorrhagic Fever (DHF). Of the 65 cases, 35 were DHF and 30 were Dengue Fever as per the WHO case definition. Among the DHF cases, hemoconcentration (>20%) was detected in 20 cases (57.14%), hypoproteinemia in 11 (31.42%) and clinical evidence of pleural effusion and or ascites in 25 (71.42%). Hemoconcentration based on area specific hematocrit cut off values was observed in 32 cases (91.42%). Ultrasonographic evidence of plasma leakage was seen in 32 cases (91.42%). In detecting plasma leakage, area specific hematocrit cut off values and ultrasonography had the highest sensitivity (91.42%), while ultrasonography had the highest negative predictive value of 84.21%. Clinical evidence of plasma leakage was more frequent than hemoconcentration or hypoproteinuria. Ultrasonography is an ideal non-invasive investigation to detect plasma leakage and area specific hematocrit values are useful as evidence of plasma leakage.