Dengue Test - IgG (Elisa)

The Dengue IgG test (ELISA) is a blood test that detects IgG-class antibodies against the dengue virus. It is used mainly to identify a past dengue infection or long-term immune response, rather than a current, acute one. Dengue is a mosquito-borne illness spread by the bite of an infected Aedes mosquito; it does not pass directly from person to person through the air. The virus is most widespread in hot, humid weather, and outbreaks are especially common during the monsoon.

When someone is infected with dengue, the immune system makes antibodies in stages. IgM appears first, indicating recent infection, while IgG appears a little later and reflects past exposure or developing immunity. Anti-dengue IgG antibodies generally appear about 5-7 days after the initial infection (sometimes sooner in a repeat infection) and are highest around the third week. In a second (secondary) dengue infection, IgG levels can rise to very high levels from around day 7. Because IgG can persist for months or even years, this test is valuable for confirming prior exposure.

Dengue ranges from a mild, flu-like illness to severe forms such as dengue haemorrhagic fever and dengue shock syndrome, which can be life-threatening. There is no specific antiviral treatment for mild dengue; most people recover within about two weeks with rest, fluids, and non-aspirin fever medicines, while severe cases need hospital care. The Dengue IgG test helps build the overall picture of a person's dengue history and is often interpreted together with the IgM test and, in early illness, the NS1 antigen test.

Your doctor may recommend a Dengue IgG test to confirm past exposure to dengue or to complete the picture in someone with dengue-like symptoms.

Common Reasons the Test Is Recommended

• To confirm a past dengue infection or prior exposure to the virus.
• In people who currently have dengue-like symptoms alongside other dengue tests.
• To help identify a secondary (repeat) dengue infection, in which IgG rises sharply.
• In those who have been exposed to the dengue virus in endemic areas.

Dengue Symptoms to Be Aware Of

• High-grade fever with headache, muscle and joint pain, and rashes.
• Nausea and vomiting.

Warning signs of severe dengue, which usually appear 24 to 48 hours after the fever subsides, include abdominal pain and tenderness, bleeding from the nose or gums, blood in vomit or stools and restlessness or exhaustion. These need urgent medical attention.

The Dengue IgG test is usually done only once after a recent dengue infection, to confirm that you have had dengue in the past. It does not normally need repeating unless you are later infected with a different serotype of the virus.

Because the test indicates past infection, it is not used to track an active infection. For a current illness, doctors monitor other markers, such as NS1, IgM, and the platelet count.

The Dengue IgG test helps clarify a person's dengue history and supports diagnosis when used with other tests:

Pro Tip: Book your Dengue IgG test on PharmEasy for convenient at-home sample collection by a trained phlebotomist - especially helpful during the monsoon when dengue is common.

The Dengue IgG test needs no special preparation, which makes it simple and convenient.

What to Expect Before the Test

• No fasting is required. If it is combined with another test that needs preparation, follow that instruction.
• For accuracy, IgG testing is best done at least 7-10 days after the start of fever, once IgG has developed.
• Tell your doctor about your symptoms, when they started, and any previous dengue infection.
• Always consult your doctor before the test for guidance.

What to Expect During the Blood Collection

A phlebotomist cleans the skin with an antiseptic, then places an elastic band around your upper arm to make the veins easier to access. A small needle is inserted into the vein, you may feel a brief pinch. Blood is collected into a labelled tube in under a minute.

What to Expect After the Test

A small cotton swab and bandage are placed over the site to stop any minor bleeding. There may be slight soreness at the needle site or mild lightheadedness. If you feel dizzy, sit and rest for a few minutes.

The Dengue IgG test measures a single parameter : the level of dengue virus IgG antibodies in the blood, reported as an index value (IV). These antibodies are produced about 7-10 days after the onset of fever.

• Dengue Virus IgG Antibody - reflects past infection or long-term immune response. In a secondary infection, it rises early and to high levels, which can help indicate a repeat infection.

Because no single dengue test gives the full picture, IgG is interpreted alongside IgM (recent infection) and, in early illness, the NS1 antigen test.

Results are reported as an index value (IV) and grouped into categories. The table below shows the typical bands.

Important Note: Reference ranges and index cut-offs vary between laboratories and kits. Always refer to the values and interpretation printed on your own report and discuss them with your doctor.

Results are interpreted alongside your symptoms, timeline, and other dengue tests.

Because IgG reflects past exposure and persists for a long time, a positive IgG on its own does not confirm a current infection. Your doctor combines it with IgM, NS1, and your clinical findings to reach a conclusion.

Disclaimer: This information is for educational purposes and provides a risk assessment only. It does not confirm a diagnosis. Always consult your doctor to interpret your dengue result correctly.

The Dengue IgG test is a routine blood draw that is generally very safe, with minor procedural risks and some limitations.

Potential Risks and Complications

Most people feel only a brief pinch. Consult your doctor if you notice:

• Persistent bleeding at the puncture site that does not stop with gentle pressure.
• Redness, swelling, or pain at the needle insertion site.
• Lightheadedness that continues after the blood draw; sit and rest before leaving.

Understanding Dengue IgG Test Limitations

• It mainly indicates past or secondary infection, not an early acute one; NS1 and IgM are used for that.
• IgG can persist for years, so a positive result does not by itself confirm current infection.
• Testing too early may miss IgG, which develops about 7-10 days after fever begins.
• Index cut-offs vary between labs and kits, so results may not be directly comparable.

The Dengue IgG test is usually part of a broader assessment. Your doctor may order additional tests depending on the stage of illness.