Know About Dengue Fever: Blood Tests and other Lab Tests

Dengue fever is caused by mosquitoes and is considered a viral infection. This means that it can transmit from one person to another when the same mosquito bites a healthy person too. This infection is typically found in areas that are tropical or subtropical. Especially in areas like Southeast Asia, Africa, and South and Central America.

What are some symptoms found in people?

The most common symptoms found in people who have dengue fever are as follows:

  • People would experience a nauseated feeling or will be seen vomiting. 
  • If the person develops rashes without any specific reason, then they may have dengue fever.
  • If they have any aches and bone pain among other pains, they might have dengue fever.

However, if a person is seen to have severe dengue, the following are the warning signs:

  • Vomiting about 3 to 4 times within a 24-hour timeline
  • Bleeding seen in the gums or the nose
  • Feeling extremely fatigued
  • Stomachache

A dengue test is required to determine if you have contracted dengue. It is typically found in people who have contracted another illness or have traveled to an area where dengue was found. If you have developed a high fever within 2 weeks of travel to such areas, then it is a must that you get the dengue test done. 

What are the different dengue tests done?

There are mainly 2 types of tests done:

  • Direct tests: These tests are done to identify the genetic signature of the virus. Direct tests are about 99% to 100% when the PCR test is done using the RT-PCR technique. The different types of Direct tests are Dengue NS1 Antigen and Dengue RT-PCR test.
  • Indirect tests: These tests are done to understand the body’s reaction to the virus. The different indirect tests done are the IgM test, IgG test, and complete blood count.

Here is a brief about each dengue test listed below:

  1. Dengue NS1 Antigen: It is a type of direct test that is conducted during the initial stages of the infection. It is done through ELISA. This is done because the NS1 antigen shows up on the first day of the infection and lasts for about 5 to 7 days. Post this timeline, it slowly exits the body which is a cause for the false readings that may come.
  2. RT-PCR test: This is another type of direct test that is conducted during the initial stages of the infection, typically within 5 to 7 days from when the person shows symptoms of the viral infection. This test detects the genetic component of the virus and is 95% specific against this virus. It needs to be done after 5 days from the time the symptoms show up for accurate results.
  3. IgM test: IgM stands for Immunoglobulin M. This test is an indirect type of test that tests for the antibodies in the blood. These antibodies show up during the initial phases of the infection. If the symptoms of dengue listed above last for more than 5 days, it is suggested to get this test done.
  4. IgG test: IgG stands for Immunoglobulin G. This test is used to determine if there is any viral infection in the later stages of this illness. IgG antibodies show up in the body after about 14 to 21 days of the infection contraction. These antibodies slowly increase and can remain in the body for about 90 days.
  5. Complete blood count: Platelet count needs to be constantly monitored. A person who contracts dengue will find a decrease in their platelet count. But a decrease in the platelet count is not sufficient to determine if a person has contracted dengue.

Here are some other dengue tests that are conducted:

  1. TLC: TLC stands for Total Leucocyte Test. This test is done to measure the total white blood cells in the body. A normal count for WBC would be around 4000 to 11000 irrespective of gender.
  2. Prothrombin test: This test is done by health professionals to determine the time taken by the plasma in the body to produce a blood clot. This is another precautionary test taken by clinics.
  3. Coagulation profile test: This test is a type of screening dengue test which is used to check if there is any abnormal clotting in the body.

How do I stay safe?

Getting a dengue test can be done as a precautionary measure but it must be done at all costs if you have contracted the virus or show any of the symptoms listed above. Here are some steps you can take to stay safe:

  • You can always consider using mosquito repellants. This will help people who are prone to mosquito bites.
  • You can make use of mosquito nets at home when you go to bed, or you can also consider spraying insecticides.
  • There are a lot of windows that come with sliding nets which you can use to keep mosquitoes out of the house.
  • Avoid allowing water to stagnate. This creates a breeding ground for mosquitoes. 


Dengue tests are designed to check for the presence of a viral infection. You must take the precautionary measures above to ensure you do not get bit by mosquitoes.