Diagnosis of Endometriosis

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Standing doctor pointing at a notepad with a clinical history

Medical history. It is very important to identify patients with suspected endometriosis and take a detailed medical history (anamnesis) with a description of the patient’s pain. One of the problems is the delay in the diagnosis, which can take as long as 10 years. What is more, between 15% and 30% of patients may not present any symptoms.

Patient lying on the examination table and doctor performing a gynaecological examination

Gynaecological examination. The gynaecologist will perform a digital vaginal examination to determine if the ovaries have increased in size, if they are relatively immobile, and whether there are any endometriotic nodules towards the rear of the cervix or in the space between the rectum and vagina. A digital rectal examination may sometimes also be used to detect nodules. The use of a speculum can occasionally provide a view of any endometriotic nodules which appear as purple lesions in the vagina.

Ultrasound on a monitor

Transvaginal ultrasound. This is currently the most important test available. It is particularly helpful in the diagnosis of endometriomas (endometrial cysts in the ovaries) and determines the shape and size of the uterus and whether adenomyosis. Nowadays, with the correct preparation, high-resolution 3D ultrasound can detect deep endometriotic lesions in the lower intestine. It can also be used to examine the urinary bladder and, when combined with abdominal ultrasound, the kidneys and ureters to rule out the presence of endometriosis in these locations.

Blood collection tube

Laboratory tests. There are no known analytical markers that can confirm the diagnosis of endometriosis. A tumour marker called CA-125 may increase in women with endometriosis. However, the increase is neither very sensitive (not all women with endometriosis show an increment) nor specific (the marker may increase due to other gynaecological pathologies) for the diagnosis of endometriosis. As such, it does not form part of the routine protocol of diagnostic tests used in the case of women with suspected endometriosis.

Magnetic Resonance Imaging or MRI machine

Magnetic resonance imaging (MRI). This is a very accurate, non-invasive imaging technique for the diagnosis of extragenital endometriosis (intestinal, urinary, pulmonary). It is used to study for retroperitoneal and nerve root compromise.

Pregnant woman undergoing gynaecological uterine surgery

Laparoscopy. In asymptomatic patients, endometriosis may be diagnosed by chance when performing a laparoscopy for some other reason. Laparoscopy is not currently recommended for the diagnosis of endometriosis.

In selected cases, based on the clinical suspicion of its presence, the following tests are carried out:


Colonoscopy of a woman

Colonoscopy. To determine if the colon’s mucous membrane is affected.


Cystoscopy. To diagnose whether the urinary bladder is affected by endometriosis.

Nuclear magnetic resonance equipment and monitor showing opaque enema

Barium enema, MRI enterography, CT enema. To examine cases of multiple intestinal compromise, the appendix, the ileum.

Woman undergoing intravenous contrast injection for urography seen on screen

Intravenous urography, renogram, renal gammagraphy. These tests may be used to complement studies investigating whether the urinary tract and renal function are affected.

Substantiated information by:

Ana Carrión Aliaga
M. Ángeles Martínez Zamora
Meritxell Gracia Quero

Published: 20 February 2018
Updated: 20 February 2018


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