Chlamydia species are readily identified and distinguished from other Chlamydia species using DNA-based tests.
Most strains of C. trachomatis are recognized by monoclonal antibodies (mAbs) to epitopes in the VS4 region of MOMP. However, these mAbs may also cross-react with two other Chlamydia species, C. suis and C. muridarum.
C. trachomatis is the single most important infectious agent associated with blindness (trachoma); approximately 84 million worldwide suffer C. trachomatis eye infections and 8 million are blinded as a result of the infection.
Nucleic acid amplification tests (NAAT). These tests find the genetic material (DNA) of Chlamydia bacteria. These tests are the most sensitive tests available, meaning that they are very accurate and that they are very unlikely to have false-negative test results. A polymerase chain reaction (PCR) test is an example of a nucleic acid amplification test. This test can also be done on a urine sample.
Nucleic acid hybridization tests (DNA probe test). A probe test also finds chlamydia DNA. A probe test is very accurate but is not as sensitive as nucleic acid amplification tests.
Enzyme-linked immunosorbent assay (ELISA, EIA). This quick test finds substances (Chlamydia antigens) that trigger the immune system to fight Chlamydia infection.
Direct fluorescent antibody test (DFA). This quick test also finds Chlamydia antigens.
Chlamydia cell culture. A test in which the suspected chlamydia sample is grown in a vial of cells. The pathogen infects the cells and after a set incubation time (48 hours) the vials are stained and viewed on a fluorescent light microscope. Cell culture is more expensive and takes longer (two days) than the other tests. The culture must be grown in a laboratory.
^Tang FF, Huang YT, Chang HL, Wong KC (1958). "Further studies on the isolation of the trachoma virus". Acta Virol.2 (3): 164–70. PMID13594716. Tang FF, Chang HL, Huang YT, Wang KC (June 1957). "Studies on the etiology of trachoma with special reference to isolation of the virus in chick embryo". Chin Med J75 (6): 429–47. PMID13461224. Tang FF, Huang YT, Chang HL, Wong KC (1957). "Isolation of trachoma virus in chick embryo". J Hyg Epidemiol Microbiol Immunol1 (2): 109–20. PMID13502539.