<prompt> In dengue infection, number of petechial spot per square inch in cubital fossa should be:5101520  <response>: 1. Dengue hemorrhagic fever is diagnosed by positive Tourniquet test which indicates number petechial spot per square inch in cubital fossa is 20 per 2.5 cm 1cm square area. 2. Tourniquet test: Done to detect thrombocytopenia. The standard method uses the blood pressure cuff. To identify dengue and chikungunya infection. Positive tourniquet test - Number of petechial spot per square inch in cubital fossa is 20. Any of the following may be present - petechiae, purpura, ecchymosis, epistaxis, gum bleeding hematemesis or melena. 3. Criteria for diagnosis of dengue hemorrhagic fever DHF: Fever - acute, high and continuous for 2-7 days. Positive tourniquet test. Enlargement of liver. 