Which of the following tests is used to monitor inflammation in the body?

The C3 complement test is utilized to monitor inflammation in the body because it assesses one of the components of the complement system, which plays a significant role in the immune response and inflammation. Elevated levels of C3 can indicate an ongoing inflammatory process, often related to infections or autoimmune diseases. This test specifically helps in understanding the state of the immune system and can provide insights into conditions that cause inflammation.

While the other tests listed have their own purposes—for example, a pregnancy test is used to detect pregnancy and the ANA test screens for autoimmune disorders—the C3 complement test is specifically relevant for monitoring inflammation, thus making it the most suitable choice in this context. Alpha 1 Antitrypsin is related to evaluating liver function and certain respiratory conditions rather than directly monitoring inflammation.