Dengue infection poses a major health problem in tropical and subtropical countries [1]. According to World Health Organization, around 50 to 100 million new infections are estimated to occur every year in more than 100 endemic countries across the world; of which around 500000 people with severe dengue require hospitalization each year and about 2.5% of those affected die [2]. The burden of the disease is so much that in the year 2012 World Health Organization classified the disease as “the most important viral disease that is transmitted by mosquitoes” [3].It has been reported in more than 100 countries and continues to spread to previously unaffected regions [4]. It is an arboviral fever caused by the dengue virus. It is caused by 5 serotypes of Dengue virus namely DENV1, DENV2, DENV3, DENV4, DENV-5 and is transmitted to human beings by the bite of Aedes mosquitoes. [5] [6].It is a mosquito borne viral infection caused by flavivirus. It starts with a simple fever and the most of the cases recover. A few number of cases may lead to life threatening complications like dengue shock syndrome and dengue hemorrhagic syndrome and these patients require careful monitoring and assessment throughout the course of the disease. Even with the advancement of medical science, there is no proper treatment for dengue and patients, suffering with it, are only provided the supportive treatment. Recently, in the patients of severe Dengue, a serious complication called as Macrophage Activation Syndrome (MAS) or Hemo-phagocytic Syndrome (HS) has been reported. This syndrome has been described as a dysregulated hyperactivated immune response caused by the disproportionate activation and proliferation of T cells and well differentiated macrophages. [7-9] This condition is an overwhelming systemic inflammation resulting in non-remitting hyper-pyrexia, hepato &splenomegaly, hemorrhage, lymphadenopathy, and central nervous system (CNS) dysfunction. MAS/HS is being increasingly reported in children suffering from severe dengue. [10-13].The WHO has classified the dengue into two major categories, non-severe variety with or without the warning signs and the severe variety. The non-severe type involves a high grade fever (104 °F or 40 °C), which is accompanied by any two of the following symptoms during the febrile phase—nausea, vomiting, rash, aches and pains, positive tourniquet test, and leukopenia. About 3–7 days after the onset of illness, fever drops to below 100 °F (38 °C) and the warningsymptoms like tenderness in the abdomen, stomach burn, nausea, vomiting, mucosal bleed, lethargy, restlessness, hepatomegaly and rising hematocrit with thrombocytopenia start to appear, which require strict medical intervention. The inevitable cases progress towards severe dengue, which is evidenced by the respiratory distress, shock, massive bleeding, leakage of plasma, and organ impairment.

According to our study serum ferritin levels can be used as an early predictor of severity of Dengue especially with in first 5 days of onset of symptoms. A cut of > 422ng/ml had a sensitivity of 100% and specificity of 81.46% to differentiate between severe and non-severe Dengue fever from our study.