It is estimated that 390 million people suffer from dengue virus infections every year

There is a steep rise in cases of dengue across India, which could be attributed to a drop in temperature and changes in the season. Although dengue infection can occur at any time of the year, it occurs more frequently in the months of July to October as they provide perfect breeding conditions for mosquitoes. A sure-shot way of keeping safe from mosquito bites and dengue is to use mosquito repellents.
Dengue Fever Testing
Dengue testing is divided into 2 categories:
Direct Tests (Detect the virus & its components): These include non-structural protein 1 (NS1) antigen and Dengue PCR tests
Indirect Tests (Detect body’s response against the virus): Include IgM and IgG antibody tests
1. Dengue NS1 Antigen: Why to get this test?
This test detects the presence of the dengue NS1 antigen in the blood. The NS 1 antigen starts to appear from the very first day of dengue infection and may be present for up to 5-7 days. Post that it starts to disappear from blood and increases the risk of false-negative results.
When to get this test: Within the first 5-7 days of the onset of symptoms
2. Dengue RT-PCR test: Why to get this test?
This test helps to diagnose dengue fever by detecting the viral genome (the genetic material of the virus) in the blood. It is the most sensitive & specific test if done in the 1st week of infection.
When to get tested: First 5 to 7 days after symptoms appear
The Dengue RT-PCR test gives you an appropriate and quick diagnosis.
3. Immunoglobulin M (IgM) test for Dengue: Why to get this test?
If you experience the symptoms of dengue continuously for more than 5 days, then this test is advised. It detects the presence of the immunoglobulin M (IgM) in the blood. This anybody starts developing after 4-5 days of infection and signifies acute infection or recent infection.
When to get tested: Between the 3rd to 9th day of the onset of symptoms
Have flu-like symptoms for more than 5 days? Get dengue IgM test done
4. Immunoglobulin G (IgG) test for Dengue: Why to get this test?
This test is used to detect a dengue infection in the later course of the disease or during recovery. The presence of IgG antibodies to the dengue virus is consistent with a past infection. Post an infection, the level of IgG increases slowly and can remain in the blood for around 90 days and in some cases, for a longer time.
When to get tested: After 14-21 days of infection or even later
Wondering if you had a dengue infection previously? Clear your doubts with IgG antibody test.
Note:
• In the 1st week of the onset of symptoms, dengue PCR test and NS1 antigen are recommended.
• Between the 3rd to 9th day, a combination of NSI antigen/ PCR and IgM antibodies is recommended..
5. Complete Blood Count (CBC)
Dengue is frequently associated with decreased platelet count (normal platelet count lies in the range of 1.5 to 4 lacs). Therefore, platelet count should be monitored carefully and regularly, especially when the fever comes down. Also there may be a drop in white blood cells count, which is called leukopenia.
When to get tested: Anytime during the course of infection
Note: Diagnosis of dengue does not depend SOLELY on platelet counts.
Remember!
Most people with dengue fever can be treated at home with adequate rest, plenty of fluids and a nutritious protein rich diet. However, it is important to get in touch with a doctor in case of severe symptoms or worsening of existing symptoms.

—The writer is a BSc Nursing student at Pacific Institute of Medical Science

UMAIR SHAFIQ KHANDAY