Chlamydia trachomatis serotype-specific antibody detection (serum/plasma) by immunoassay

What This Test Measures

The test detects antibodies produced by your immune system in response to *Chlamydia trachomatis*—a bacterium that can infect the genitals, throat, or eyes. These antibodies appear after your body has been exposed to the infection, often weeks to months later. The test specifically looks for antibodies against different serotypes (strains) of the bacterium, which can help identify the type of infection you may have had.

Why It’s Ordered

Your healthcare provider may order this test if you have symptoms like unusual discharge, pain during urination, or unexplained eye redness. It’s also used in screening for sexually transmitted infections (STIs), especially in high-risk groups, or to confirm a diagnosis after exposure.

Sample Collection and Preparation

A blood sample is drawn from a vein in your arm. The blood is processed to separate serum or plasma, which is then tested for antibodies using an immunoassay method. This process typically takes a few minutes, and the results are analyzed in a lab.

Test Limitations and Considerations

This test cannot diagnose an active infection—it only shows past exposure. False negatives may occur if the infection was recent or treated early. Antibody levels can also decrease over time, so repeated testing may be needed for confirmation.