CHLAMYDIA TRACHOMATIS ANTIBODY IGM, SERUM

Chlamydia trachomatis Antibody IgM, Serum

What it is

The Chlamydia trachomatis Antibody IgM, Serum test detects IgM class antibodies in the blood that develop in response to infection by Chlamydia trachomatis. IgM antibodies appear early in the course of infection, making this test valuable for diagnosing recent or acute chlamydial infections. Chlamydia trachomatis is one of the most common sexually transmitted infections (STIs) worldwide.

Uses

This test is used to identify acute or recent Chlamydia trachomatis infection. It is especially helpful in distinguishing current infection from past exposure (IgG antibodies). It may be used when patients present with symptoms of sexually transmitted infections, unexplained infertility, or pelvic inflammatory disease. It can also support diagnosis in neonatal infections acquired during birth.

Symptoms That May Lead to the Test

Doctors may recommend this test if you have symptoms such as painful urination, abnormal genital discharge, pelvic pain, painful intercourse, testicular pain, or irregular vaginal bleeding. In women, untreated infection can lead to pelvic inflammatory disease (PID) and infertility. In men, it can cause urethritis and epididymitis. Infants exposed during delivery may present with conjunctivitis or pneumonia.

Abnormal Results

Positive IgM: Indicates a recent or ongoing Chlamydia trachomatis infection. Follow-up with nucleic acid amplification testing (NAAT) is often recommended for confirmation, as antibody tests may cross-react with other chlamydial species.

Negative IgM: Suggests no evidence of a current or recent infection. However, very early infection cannot be excluded since IgM antibodies may not have developed yet. Additional IgG or NAAT testing may be needed.

Risks

The test requires a simple blood sample, with minimal risks such as mild pain, slight bruising, or dizziness at the puncture site. These side effects are temporary and rare.