Dengue fever is mosquito born seasonal viral illness. There is increasing burden of dengue in India. Seeing the increasing number of cases and epidemics worldwide, WHO reclassified dengue classification in 2009. There has been very few studies of dengue fever based on new classification system and especially from this part of country, so we did a study of clinical spectrum and laboratory profile of dengue fever patients according to WHO classification 2009.

Methods: A prospective observational study, was carried out in Sir Sundar Lal hospital, Institute of medical sciences, Banaras Hindu University, Varanasi, after ethical approval from ethical committee of institute and taking proper consent from patients. Patients with incomplete follow up and records were excluded. Daily evolution of sign and symptoms, warning signs, postural fall of blood pressure were recorded. Suspected cases were considered as case of dengue fever based on the result of rapid diagnostic kit method. Laboratory profile like complete blood count, haematocrit, liver and renal function test, PT/INR (prothrombin time), activated partial thromboplastin time (aPTT), chest x-ray, electrocardiography (ECG) and ultrasonography (USG) abdomen and chest were documented.