Serum or Plasma Substance Concentration by Immunoassay (e.g., Anti-SARS-CoV-2 Antibody)

What This Test Measures

This test looks for specific proteins called antibodies in your blood that your immune system creates when it encounters the SARS-CoV-2 virus. Antibodies are part of your body’s defense system and can help identify if you’ve been exposed to the virus at some point, even if you didn’t get sick or had mild symptoms. The test uses a method called immunoassay to detect these antibodies in serum or plasma from a blood sample.

Why You Might Need This Test

Healthcare providers may order this test to check for immunity after recovering from COVID-19, screen for past infection in asymptomatic individuals, or assess exposure in high-risk settings. It’s also sometimes used to monitor ongoing immunity in people who’ve received vaccines or natural infection.

Sample Collection and Preparation

A small blood sample is drawn from a vein, usually in your arm. The blood is then processed to separate serum or plasma, which is sent to the lab for testing. This process is quick and typically done in a doctor’s office or clinic.

Test Results and Interpretation

Results are qualitative (positive or negative) and indicate whether antibodies were detected. A positive result suggests exposure to the virus, but it doesn’t always mean you were sick. Negative results mean no detectable antibodies were found at the time of testing.