**7.2 Cytology and cell culture**

Cytologic diagnosis is used to evaluate endocervical scrapings in genitourinary infection, but cultures are difficult to gather, not easy to analyze, and their sensitivity is low, many false-negative results are encountered. Because of the need for expert laboratory skills, they are also expensive. They may be incompatible when trying to assess a large number of patients. But they are still mandatory in certain clinical situations such as legal indications like rape or sexual abuse because of their high specificity (100%). Cell culture can also be the choice for rectal specimens because of the confounding effect of the stool microorganisms in other tests when interpreting the results.

*C. trachomatis* can be grown well in cell lines like McCoy and HeLa cells. Incubation time is 40–72 hours, depending on the cell type and specific biovar. Intracytoplasmic inclusions can be captured either by Giemsa stains or by immunofluorescent staining with monoclonal antibodies.
