By Dr Harsh Sharma, DHMS, BHMS
Published August 13, 2014, Last updated July 11, 2018
Diagnosing dengue fever poses a challenge as it may mimic any ordinary viral fever or chikengunya or west nile fever. In most of the cases, the intense pains in the body, muscles, head and behind the eyes raise suspicion of Dengue fever but the presence of these symptoms cannot by themselves be a sure guide to the diagnosis of Dengue fever. Therefore it is necessary to understand what would constitute a confirmed diagnosis of the Dengue fever. At the same time, it will help in the treatment and management of the disease. Before we find out the tests that help in the diagnosis of Dengue, it is necessary to understand the basics of the spread, its vector and clinical picture. For detailed information about these, you can see https://www.homeopathicdoctor.co.in/dengue-treatment-and-prevention-in-homeopathy/
Vector or spread of Dengue Viruses
Dengue is spread to humans by the infected Aedes mosquitoes, primarily the Aedes Egypti though Aedes albopictus, Aedes polynesiensis and Aedes scutellaris have also been known to act as vectors.
Types of Dengue Viruses
Dengue viruses are of 4 different types—numbered 1 to 4 and named DEN-1, DEN-2, DEN-3 and DEN-4.
Blood tests for diagnosis dengue and management of Dengue fever
a) CBC A complete blood count will give a picture of the WBC count as well as the platelets. A CBC test done in the early stage of the fever can form a baseline for checking the progress of the disease. A decreasing white blood cell count makes Dengue quite likely. At the same time, it is important to know the platelet count. Platelets are the blood cells that are responsible for clotting of blood. In any case of dengue fever, a falling platelet count is always alarming as it can trigger bleeding within the body, also known as the Dengue Hemorrhagic Fever. This can become a medical emergency as it is often life threatening.
b) Haematocrit A Haematocrit can also become a base for checking the progress of the disease and becomes an important tool for the management of the Dengue fever. An early haematocrit forms a baseline and should be repeated. A rapid fall in the platelets coupled with an increasing haematocrit suggests a critical possibility.
c) NS1 The Non Structural protein 1 of the Dengue Virus is a useful tool for the diagnosis of Dengue in the acute stage. It is one of the tests commonly available in the routine testing kits. NS1 antigen has been known to be detected as early as Day 1 of the onset of symptoms.
d) IgG The IgG ELISA is used for detection of recent as well as past infections with dengue viruses. IgG antibodies once formed may remain for the whole of the life but a fourfold or greater increase of IgG antibodies may show a recent infection.
e) IgM The IgM ELISA test is also quite sensitive and specific but relevant only after 5 days of onset of fever.