## 1 Introduction  
Dengue is an acute febrile disease caused by dengue virus (DENV). Commonly, dengue incidences happen in tropical and subtropical countries, such as South America, Southeast Asia, etc. [1]. Dengue incidences usually occur in the rainy season, and happen in urban and suburban areas. Based on a study that analyzed 130 countries, there were around 9221 dengue deaths per year from 1990 to 2013, with the lowest of 8277 in 1992, and the highest of 11,302 in 2010 [2]. Dengue had made Indonesia suffered the most significant economic loss in Southeast Asia. The average annual economic burden of dengue in Indonesia was approximately USD 381.5 million. Indonesia has the highest dengue infection rate in Southeast Asia and the second-highest dengue infection rate in the world after Brazil [3]. In 2017, there were 59,047 Dengue Hemorrhagic Fever (DHF) cases and 444 DHF-associated deaths in Indonesia, with 0.75% case fatality rate and 22.55 incidence rate per 100,000 person-years [4]. In 2018, the national incidence of dengue was 24.75 cases per 100,000 population, resulting in 467 deaths [5]. DENV is a member of the family Flaviviridae and genus Flavivirus [6]. DENV is transferred by _Aedes aegypti_ and _Aedes albopictus_ female mosquitoes [7]. Those female mosquitoes consume blood as their regular meal to mature their eggs [8]. They fulfill their need for blood by biting humans. The incubation period of DENV is around 4 to 10 days. After the incubation period ends, an infected mosquito can transfer DENV in its lifetime [9]. There are four serotypes of DENV, which are DENV-1, 2, 3, and 4. A DENV-infected person can be infected by one serotype of DENV or more [10]. Dengue consists of three clinical phases, which are febrile phase (occurs on the first until the third day of fever), critical phase (occurs on the fourth until sixth day of fever), and recovery phase (occurs on the seventh day of fever or afterwards). The common clinical symptoms of dengue are as follows: during the febrile phase, the symptoms are high fever, headache, nausea, myalgia, arthralgia, malaise, retro-orbital pain, and vomiting [11]. During the critical phase, the symptoms are thrombocytopenia, leukocytopenia, and plasma leakage, which is clinically manifested by hemoconcentration, pleural effusion, and/or ascites. Patients may also experience severe bleeding and shock [11]. During the recovery phase, the extravasated fluid is re-absorbed into the intravascular compartment. Some patients may experience an erythemata rash. The severity level of dengue consists of Dengue Fever (DF), Dengue Hemorrhagic Fever (DHF), and Dengue Shock Syndrome (DSS) [12]. DF is commonly classified as dengue, while DHF and DSS are commonly classified as severe dengue. The main difference between dengue and severe dengue is, patients who suffer severe dengue experience plasma leakage, while patients who suffer dengue do not. In this research, we only considered level DF and DHF. DHF itself was divided into two different levels, which were DHF grade 1 and DHF grade 2. The gold standard to confirm a DENV infection are Reverse Transcription-Polymerase Chain Reaction (RT-PCR) test, culture of DENV, hemagglutination inhibition test, laboratory test, and tourniquet test. A suspected person can go through a laboratory test that measures hematocrit, thrombocyte (platelet count), and white blood cell (WBC). DENV infection will decrease in platelet count below 100,000 per \(\upmu\)L between the third to eighth day onset of fever, and an increase in hematocrit of 20% or more. A positive tourniquet test also indicates that the corresponding patient might suffer dengue. Laboratory test parameters that we analyzed consist of hematocrit, hemoglobin, platelet count, WBC, monocyte, lymphocyte, and neutrophil. In this research, we developed models that can predict the severity level of a dengue patient, based on the values of the seven laboratory test parameters. In other words, the laboratory test parameters were used as predictors to predict the severity level of a dengue patient.