The Dengue NS1 Antigen ELISA test is designed to detect the non-structural protein 1 (NS1) of the dengue virus in a blood sample. Any foreign material that enters the body (such as viruses) is called an antigen. Detection of NS1 is possible during the acute phase (or first 7 days) of dengue fever. This signifies that the NS1 test can help in the early diagnosis of dengue and the initiation of appropriate medical care.

Dengue fever, a mosquito-borne illness, is caused by one of the four serotypes (or strains) of the dengue virus that belongs to the genus Flavivirus. When an infected mosquito bites a person, the dengue virus enters the bloodstream and begins to replicate. The virus and the immune system response result in the symptoms associated with dengue fever. The Dengue NS1 test can detect the virus in the blood within the first 7 days of experiencing symptoms. Studies also show that the levels of NS1 antigen in the blood correlate with the severity of the disease, with higher levels seen in those with severe infection. Thus, Dengue antigen test can provide valuable diagnostic information in dengue infection.

Given below is an overview of the test's preparation:

Prerequisites

The Dengue NS1 test does not need fasting.

Best Time to Get Tested

The Dengue NS1 Antigen test can be done at any time of the day.

Eligibility for Dengue NS1 ELISA Test

Dengue NS1 test should be done if you live in or have travelled to an area where dengue is common and have been having recent symptoms indicative of dengue, such as high fever, rash, muscle and joint pain, pain behind the eyes, nausea and vomiting.

Cautions Before Taking Dengue NS1 ELISA Test

No special cautions are needed before taking a Dengue NS1 test.

You should take a Dengue NS1 test if you live in or have been to an area where dengue fever is common and have recently been showing symptoms of dengue. The symptoms of dengue fever usually arise within 4 to 10 days after a mosquito bite and continue for 3 to 7 days. Symptoms typically include a sudden fever reaching up to 104°F or above along with any of the following symptoms:

• Rash

• Nausea and vomiting

• Severe pain behind the eyes

• Headache

• Muscle, bone or joint pain

If neglected, some individuals may develop a life-threatening worsening of symptoms called dengue hemorrhagic fever that causes nose bleeds, bleeding gums, abdominal pain, frequent vomiting, throwing up blood, blood in stools, and extreme tiredness. The risk of severe dengue underscores the need for early detection and treatment of this infection.

Since the NS1 antigen is detectable in the blood during the acute phase of infection, the NS1 test is done in the first 7 days of experiencing symptoms. After the first week, the NS1 test may not be as sensitive in diagnosing dengue.

The Dengue Antigen test thus helps healthcare providers with early detection of dengue, confirming dengue infection, and ruling out other non-dengue illnesses that have similar symptoms.

The below table explains the interpretation of results of a Dengue NS1 ELISA test:

It is important to note that interference may occur in some cases where the blood sample contains antibodies against test components. For example, when testing for dengue virus, the test might also detect antibodies from cross-reactivity with other Flaviviruses or other non-infectious conditions, potentially leading to false-positive results or misinterpretation of the test. Therefore, when interpreting test results, it's essential to consider the patient's clinical history to ensure an accurate diagnosis. In such cases, using both NS1 detection and IgM Antibody test can enhance the accuracy of diagnosing dengue infection. It’s also important to note that the dengue NS1 ELISA is the preferred test within the initial 7 days of symptom onset. After 7-10 days, dengue fever IgG and IgM antibody tests are recommended.