Table 1.

DF/DHF	Grade	Signs and symptoms	Laboratory
DF	With or without haemorrhagic manifestations	Fever with two of the following: (i) Headache. (ii) Retro-orbital pain. (iii) Myalgia. (iv) Arthtralgia/bone pain. (v) Rash. (vi) Haemorrhagic manifestations. (vii) No evidence of plasma leakage.	Leucopenia (wbc ≤5000 cells/mm3). (i) Thrombocytopenia (platelet count <150 000 cells/mm3). (ii) Rising haematocrit (5%–10%). (iii) No evidence of plasma loss.
DHF	I	Fever and haemorrhagic manifestation (positive tourniquet test) and evidence of plasma leakage.	Thrombocytopenia <100 000 cells/mm3; HCT rise ≥20%.
DHF	II	As in Grade I plus spontaneous bleeding.	Thrombocytopenia <100 000 cells/mm3; HCT rise ≥20%.
DHF	III	As in Grade I or II plus circulatory failure (weak pulse, narrow pulse pressure (≤20 mmHg), hypotension, restlessness).	Thrombocytopenia <100 000 cells/mm3; HCT rise ≥20%.
DHF	IV	As in Grade III plus profound shock with undetectable BP and pulse.	Thrombocytopenia < 100 000 cells/mm3; HCT rise ≥20%.