Diagnosis of chlamydial infection

Abstract

Chlamydial infection affects young, sexually active persons. As the most common bacterial sexually transmitted infection in the world, Chlamydia can lead to severe consequences in reproductive system, including chronic pelvic inflammatory disease, ectopic pregnancy and tubal factor infertility. On the other hand, although in large number of women the immune response is capable of removing the pathogen, infection can ascendently spread to the upper reproductive tract where can develop into persistent infection. Diagnostic procedures for detecting chlamydial infection include direct and indirect methods. Localized acute infections are detected by direct pathogen detection using cell culture, tests for qualitative detection of antigens, hybridization tests and nucleic acid amplification tests. When the infection has passed on the upper genital tract, especially in the case of a developed persistent infection, the diagnosis is usually made by indirect methods - the detection of antibodies to chlamydial antigens. Direct pathogen detection in patient material is necessary for the diagnosis of an acute chlamydial infection. Of all direct diagnostic tests, nucleic acid amplification tests are the only tests recommended by European and American Center for Disease Control and Prevention which can be used for the diagnosis of an acute chlamydial infection. These tests are recommended for their high sensitivity, specificity and diagnostic speed. Indirect serological tests which detect immune response or antibodies specific to chlamydial antigens are recommended for the detection of persistent chlamydial infection. Serum samples are relatively easy to collect, while tissue samples from the place of persistent infection are often hard to reach or unavailable.