Influenza Virus Rapid Antigen Test (Serum/Plasma)

How the Test Works

The test uses a rapid immunoassay (fia) method to identify specific proteins (antigens) produced by the influenza virus shortly after infection. A small blood sample is collected, and antibodies in the test react with these antigens if present, producing a visible result within minutes.

What to Expect Before the Test

No special preparation is needed. You may have a blood draw at a clinic, doctor’s office, or lab. If done at home, follow the manufacturer’s instructions carefully.

What the Test Results Mean

A positive result indicates likely recent influenza infection. A negative result means the test did not detect the virus antigens at the time of testing, but infection could still be present if symptoms are severe or if testing was done too early. False negatives may occur if the test was done too soon after exposure.

When You Might Need This Test

Your healthcare provider may recommend this test if you have flu-like symptoms (fever, cough, sore throat) and suspect influenza, especially if you’re at higher risk for complications (e.g., elderly, immunocompromised, or pregnant). It can also be used in outbreak settings or for rapid screening in healthcare settings.