The Chlamydia IgM test is a blood test that detects the presence of IgM antibodies to Chlamydia trachomatis, a sexually transmitted bacteria that can cause a range of infections including urethritis, cervicitis, and pelvic inflammatory disease. IgM antibodies are produced by the immune system in response to a recent Chlamydia trachomatis infection and may persist in the blood for several weeks after the infection has resolved. The test may be used to diagnose a current or recent infection, determine if an individual has been recently exposed to the bacteria, or screen individuals who are at risk of infection. The test is typically performed on a blood sample and sent to a laboratory for analysis. Results are reported as a numerical value or a positive/negative result, depending on the laboratory’s reference range. The Chlamydia IgM test is not the primary test for Chlamydia infection, and other tests, such as nucleic acid amplification tests (NAATs), are more commonly used.