The Dengue NS1 Antigen (NS1 Ag) test detects the presence of the NS1 protein, a non-structural protein secreted by the dengue virus during active infection. It is used for the early diagnosis of dengue fever, typically within the first 1–7 days of symptom onset, before antibodies develop.

Positive Test Risk Factors:

• • Early phase of dengue infection (usually day 1–7 of symptoms).
  • Higher viremia levels, increasing the risk of severe complications.
  • Potential for progression to severe dengue, especially with warning signs (e.g., bleeding, persistent vomiting, or severe abdominal pain).

Complications to Monitor:

• • Dengue Hemorrhagic Fever: Increased vascular permeability, thrombocytopenia, and bleeding.
  • Dengue Shock Syndrome: Critical drop in blood pressure leading to organ failure.

Normal Range:

• Negative: NS1 antigen not detected.

NS1 Antigen Positive:

• Indicates an active dengue infection in its early phase.
• Confirms the presence of dengue virus.
• Requires further clinical evaluation and monitoring for potential complications like dengue hemorrhagic fever or dengue shock syndrome.

NS1 Antigen Negative:

• Absence of dengue infection.
• Testing performed outside the diagnostic window (e.g., later in the illness when antibodies dominate).
• Low levels of antigen undetectable by the test.

Blood Sample (Serum or Plasma):

• Collected via venipuncture.
• Serum/plasma is analyzed for NS1 antigen presence.