**7. Differential diagnosis and diagnostic workup**

Since *Chlamydia trachomatis* can cause a wide spectrum of clinical presentations and manifestations, differential diagnosis of various signs and symptoms are also broad. Similar clinical manifestations affecting each body part should be considered carefully for other etiologies. The most common diseases that should be considered in differential diagnosis can be listed as: vaginal candidiasis, bacterial vaginosis, gonorrhea*,Trichomonas vaginalis*, *Ureaplasma* or *Mycoplasma genitalium* infection, foreign body, genital herpes, urinary tract infection, appendicitis, constipation, ovarian cysts, endometriosis adenomyosis, inflammatory bowel disease, allergy, cervical or endometrial polyp, cervical cancer, cervical ectropion, syphilis, chancroid, granuloma inguinale, leiomyoma, and pregnancy.

Considering the *C. trachomatis* infections, trachoma is the only one that can be diagnosed based upon clinical findings. All other chlamydial infections require laboratory confirmation. All patients with any sexually transmitted disease (STD) should also be evaluated for chlamydial infection because of the possibility of coinfection. Based on the patient's sexual practices achieved from history; endocervical, urethral, rectal, or oropharyngeal specimens should be collected and evaluated for *C. trachomatis* infection in both males and females [54]. Today, the gold standard for the diagnosis of urogenital chlamydia infections is nucleic acid amplification testing (NAAT) [55, 56]. A voided urine sample, whether first-void or midstream can be used to detect the chlamydial organism for nucleic acid amplification testing (NAAT). Self-collected vaginal swab specimens are shown to be equivalent in sensitivity and specificity to those collected by a clinician using NAATs [55, 57, 58]. If the newly

mother had a documented untreated chlamydial infection during pregnancy, the infant should be treated doubtlessly without a need for confirmation.

#### **7.1 Basic laboratory tests**

A complete blood count (CBC) must be done if pelvic inflammatory disease (PID) is suspected. HIV testing, testing sexual partners for Chlamydia and a Pap smear test should also be considered. A pregnancy test is essential for females when determining the treatment because pregnancy is a contraindication for some treatment options.
