Endometriosis Diagnostics

Laboratory Tests and Ancillaries

Urinalysis and urine culture are used to identify pain originating in the urinary tract (eg cystitis, stones). Pregnancy tests and tests for sexually transmitted infections (STIs) like gonorrhea and chlamydia, when appropriate, are also utilized. Lastly, it must be noted that there is no available blood test that can reliably diagnose endometriosis.

Laparoscopy

Laparoscopy is the gold standard for diagnosis unless lesions are visible in the vagina. It may also be used for therapeutic purposes. It should not be done during or within three months of hormonal treatment to avoid underdiagnosis.

Biopsy and histopathologic study of at least one lesion is ideal. The three cardinal features (ie ectopic endometrial glands, ectopic endometrial stroma, hemorrhage into adjacent tissue) should be present. In adolescents, the features of endometriosis may be atypical (ie clear vesicles, red lesions).

A negative laparoscopy does not exclude the diagnosis of endometriosis. Depending on the severity of the disease found, it is best to remove the endometriotic lesion at the same time. Differential diagnoses can be excluded by biopsy. 

Laparoscopic Classifications

The Revised American Society for Reproductive Medicine (rASRM) score (formerly the Revised American Fertility Society [rAFS] Score), which is based on the location, extent and severity of lesions, noted aspects including bilaterality, depth of invasion, size, involvement of the ovary and cul-de-sac, and density of adhesions. It does not take into account the retroperitoneal structures and deep infiltrating endometriosis. Scoring is as follows:

• 1-5 for minimal disease (stage I)
• 6-15 for mild disease (stage II)
• 16-40 for moderate disease (stage III)
• >40 for severe disease (stage IV)

The Enzian Staging System takes into account the presence of deep infiltrating endometriosis. It supplements the rASRM score with a description of deep infiltrating endometriosis, retroperitoneal structures, and other organ involvement.

Serum CA-125

Women with endometriosis may have high serum CA-125 concentrations but endometriosis may still be present despite normal CA-125. It has no value as a diagnostic tool in endometriosis, though it may be used to assess the presence of an undiagnosed adnexal mass. It is also elevated in ovarian epithelial neoplasia, myoma, adenomyosis, acute pelvic inflammatory disease (PID), ovarian cyst, and pregnancy.

Biopsy

A biopsy may be considered in suspected endometriosis lesions and endometriomas to help confirm the diagnosis and exclude possible malignancy. It is recommended for the diagnosis of patients with mild to moderate endometriosis. In patients with endometriosis, the prevalence of ovarian cancer is <1%. Biopsy can help rule out other alternative diagnoses (eg endosalpingiosis, mesothelial hyperplasia, hemosiderin deposition, hemangiomas, adrenal rests, inflammatory changes, splenosis, and reactions to oil-based radiographic dyes).

Imaging

Transvaginal Sonography (TVS)

Transvaginal sonography is considered the first-line imaging tool to examine suspected endometriosis. It should be performed to determine whether a pelvic mass or structural anomaly is present. It is useful in diagnosing or excluding rectosigmoid endometriosis.

It may identify an ovarian endometrioma and help identify other structural causes of pelvic pain, such as ovarian cysts, torsion, tumors, genital tract anomalies, and appendicitis. It also distinguishes endometrioma from other ovarian cysts with 83% sensitivity and 89% specificity. Ovarian endometrioma may be diagnosed in premenopausal women with findings of ground glass echogenicity, 1-4 compartments, and the absence of papillary structures with blood flow. Dynamic TVS with or without gel sonovaginography is accurate in diagnosing deep infiltrating endometriosis using the International Deep Endometriosis Analysis (IDEA) approach. If TVS is not appropriate, a transabdominal ultrasound may be done.

Endometriosis_Diagnostics