Oct 2020

Endometriosis: But your tests are all negative?


So often we get questions in our Facebook group about diagnostic studies for endometriosis. Patients are told repeatedly, your MRI/CT Scan/US/colonoscopy showed nothing, so you are disease free. Often they are told by family, friends, and doctors alike to stop obsessing about their symptoms, because they do not have endometriosis. This makes the path to diagnosis long and difficult for the patient. Since classic endometriosis symptoms are so pervasive and painful, these women persist in seeking answers. Still, on average, it takes 9 years to get a diagnosis.

While scans can RULE IN endometriosis (particularly deep infiltrating endometriosis and endometriomas), they CANNOT DEFINITIVELY RULE OUT endometriosis. And yet, sadly, patients- who have failed all the “usual” symptomatic treatment options- are not offered surgery because their scans are “negative”. And yet they are still in disabling pain! For those who have pushed through and had surgery with someone who knows what and where to look, those same patients are found to have active, painful, and removable disease!

Key points:

  • “The definitive diagnosis of endometriosis can only be made by histopathology showing endometrial glands and stroma with varying degree of inflammation and fibrosis.” (Rafique & Decherney, 2017)
  • “Currently, there are no non?invasive tests available in clinical practice to accurately diagnose endometriosis…. Laparoscopy remains the gold standard for the diagnosis of endometriosis and using any non?invasive tests should only be undertaken in a research setting.” (Nisenblat et al., 2016)


A colonoscopy, as part of a work-up for endometriosis, is not routinely ordered (Milone et al., 2015). However, endometriosis near or on the bowel can cause bleeding from the bowel, which prompts an order for a colonoscopy to rule out other problems. However, endometriosis rarely goes through the full thickness of the bowel where it could be seen during a colonoscopy, therefore it does not rule out endometriosis on or near the bowel. In one study, a colonoscopy only found suggestive findings of intestinal involvement in 4% of the patients (who later were found to have it during surgery) and failed to find intestinal endometriosis in 92% of the patients (Milone et al., 2015).

MRI’s, CT Scans, and Ultrasounds:

Magnetic resonance imaging (MRI’s), CT scans, and ultrasounds can help rule out certain conditions and, in some cases, confirm the likelihood that endometriosis is present. MRI’s and ultrasounds can be helpful in diagnosing deeply infiltrating endometriosis and ovarian endometriotic cysts; however, they cannot rule out the presence of all endometriosis (Ferrero, 2019). While CT scans are “not useful in the diagnosis of endometriosis”, they are useful in detecting “ureteral involvement and possible renal insufficiency” (Hsu, Khachikyan, & Stratton, 2010). Peritoneal lesions are simply too small to be picked up on scans, but their presence can cause substantial peritoneal irritation and bleeding in the surrounding tissue, leading to peritoneal signs and symptoms (pallor, bloating, severe pain, rebound tenderness, painful pelvic exams, nausea, diarrhea, constipation, anxiety, restlessness, etc.). We know that the size and number of lesions do not equate with the amount of pain patients experience, so a few lesions can result in disabling pain and ALL diagnostic studies may be negative. Some invasive lesions of ligaments, organs, pelvic sidewalls likewise will not show up on scans/tests. While advances in techniques are being made, the use of those are not mainstream yet (Leonardi et al., 2020; Leonardi, Robledo, Espada, Vanza, & Condous, 2020).


“By taking a careful history of patients and considering their symptoms, the disease may be greatly suspected” (Riazi et al, 2015). Symptoms such as menstrual pain, pelvic pain, pain with sex, noncyclic pain, urinary symptoms, and painful defecation during menses all had a higher predictive value of a diagnosis of endometriosis (Riazi et al., 2015). Some other symptoms might include: pain with exercise, nausea, constipation, diarrhea (often diagnosed as irritable bowel syndrome but more often than not related to endo), bleeding from the rectum, pain with a full bladder, fatigue, and so forth.  It can also be difficult to correlate symptoms as part of a whole picture. This is why it is important for the patient to be self-educated, know the correlating symptoms, and be able to give a detailed summary.

Physical Exam:

Most patients have a normal physical exam making it a poor indicator (Hsu, Khachikyan, & Stratton, 2010). However, if the examiner finds abnormalities such as tenderness, nodularity, masses, or a fixed uterus, this can “suggest the benefit of imaging prior to surgery” (Hsu, Khachikyan, & Stratton, 2010).


We have even seen patients having had a laparoscopy being told that “your ovaries tubes and uterus are pristine, you have no endo”. But given that the uterus, fallopian tubes, and ovaries are well down the list on frequency of involvement, a pronouncement of pristine organs does not mean that endometriosis is not present. In most cases, the disease will be found elsewhere.

Hormonal Suppression:

Another indicator some use to determine if endometriosis is likely is if there is a reduction in symptoms in response to hormonal medications. However, “relief of chronic pelvic pain symptoms, or lack of response, with preoperative hormonal therapy is not an accurate predictor of presence or absence of histologically confirmed endometriosis at laparoscopy” (Jenkins, Liu, & White, 2008). Hormonal therapy may affect the inflammation of the lesions and may make it more difficult for some to be able to detect lesions (and therefore miss the disease). While the suppression of ovulation can help when addressing the ovary, it can also cause missed disease in subtle and typical lesions, smaller ovarian lesions, deep endometriosis, and appendicular endometriosis (Koninckx, 2016). Also, while hormonal suppression may help some with symptom management, it does not eradicate the lesions (Vercellini et al., 2014).

Factors Affecting the Tests:

While diagnostic studies can helpful in many situations, they are inadequate alone in the determination of the presence or absence of endometriosis. The sensitivity of the test is only as good as the interpreter’s knowledge and skills of how to detect signs of endometriosis (Leonardi et al., 2020; Exacoustos, Manganaro, & Zupi, 2014). We are starting to see some gynecologists doing their own vaginal ultrasounds and picking up adenomyosis where others say it is not in evidence. Likewise, some radiologists, as they have grown familiar with larger lesions of endometriosis on the bowel or rectal vaginal areas, are picking up the possibilities. However, NEGATIVE STUDIES DO NOT RULE OUT ENDOMETRIOSIS.  Symptoms/history and pelvic exams that indicate a suspicion of endometriosis should dictate further care. The gold standard for diagnosis remains the laparoscopic exam- which hopefully will offer excision of the disease during the same procedure.


These tests can be very useful. Some doctors use MRI’s or ultrasounds as part of the pre-operative evaluation to prepare for what needs to be done at surgery (such as consulting a gastrointestinal surgeon to be a part of the surgical team in the suspicion of bowel endometriosis). However, at this time, negative tests do not definitively rule out the diagnosis of endometriosis.

Read more about magnetic resonance imaging (MRI’s), ultrasounds, and other tests in the diagnosis of endometriosis here.


Exacoustos, C., Manganaro, L., & Zupi, E. (2014). Imaging for the evaluation of endometriosis and adenomyosis. Best practice & research Clinical obstetrics & gynaecology28(5), 655-681. Retrieved from

Ferrero, S. (2019). Proteomics in the diagnosis of endometriosis: opportunities and challenges. PROTEOMICS–Clinical Applications13(3), 1800183. Retrieved from

Hsu, A. L., Khachikyan, I., & Stratton, P. (2010). Invasive and non-invasive methods for the diagnosis of endometriosis. Clinical obstetrics and gynecology53(2), 413. Retrieved from

Jenkins, T. R., Liu, C. Y., & White, J. (2008). Does response to hormonal therapy predict presence or absence of endometriosis?. Journal of minimally invasive gynecology15(1), 82-86. Retrieved from

Koninckx, P. (2016). Guidelines for medical therapy before and after surgery for endometriosis. Retrieved from

Leonardi, M., Ong, J., Espada, M., Stamatopoulos, N., Georgousopoulou, E., Hudelist, G., & Condous, G. (2020). One?size?fits?all approach does not work for gynecology trainees learning endometriosis ultrasound skills. Journal of Ultrasound in Medicine. Retrieved from

Leonardi, M., Robledo, K. P., Espada, M., Vanza, K., & Condous, G. (2020). SonoPODography: A new diagnostic technique for visualizing superficial endometriosis. European Journal of Obstetrics & Gynecology and Reproductive Biology. Retrieved from

Milone, M., Mollo, A., Musella, M., Maietta, P., Fernandez, L. M. S., Shatalova, O., … & Milone, F. (2015). Role of colonoscopy in the diagnostic work-up of bowel endometriosis. World Journal of Gastroenterology: WJG21(16), 4997. Retrieved from

Nisenblat, V., Prentice, L., Bossuyt, P. M., Farquhar, C., Hull, M. L., & Johnson, N. (2016). Combination of the non?invasive tests for the diagnosis of endometriosis. Cochrane Database of Systematic Reviews, (7).  Retrieved from

Rafique, S., & Decherney, A. H. (2017). Medical management of endometriosis. Clinical obstetrics and gynecology60(3), 485.  Retrieved from

Riazi, H., Tehranian, N., Ziaei, S., Mohammadi, E., Hajizadeh, E., & Montazeri, A. (2015). Clinical diagnosis of pelvic endometriosis: a scoping review. BMC women’s health15(1), 39. Retrieved from

Vercellini, P., Viganò, P., Somigliana, E., & Fedele, L. (2014). Endometriosis: pathogenesis and treatment. Nature Reviews Endocrinology10(5), 261. Retrieved from

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