Diagnosing endometriosis typically involves a combination of symptom evaluation, pelvic exam, imaging, and sometimes surgery. There is no single quick test that confirms it, which is a major reason diagnosis takes so long. Reports show delays ranging from less than a year to 12 years depending on geography and healthcare access, with some patients waiting up to a decade.
Why Diagnosis Takes So Long
Endometriosis symptoms overlap heavily with other conditions. Pelvic pain, painful periods, pain during sex, and digestive issues can also point to irritable bowel syndrome, pelvic inflammatory disease, adhesions from prior surgery, or adenomyosis (a related condition where tissue grows into the muscular wall of the uterus). Many people are told their pain is “just bad periods” for years before anyone investigates further.
The lack of a simple blood test adds to the problem. International guidelines from the European Society of Human Reproduction and Embryology (ESHRE) explicitly recommend against using blood biomarkers, urine, or menstrual fluid tests to diagnose endometriosis. None has proven reliable enough for clinical use. This means the diagnostic path still relies on piecing together your symptoms, physical findings, and imaging results.
Symptom Evaluation: The Starting Point
The first step is a detailed conversation about your symptoms. Clinicians are advised to consider endometriosis when someone reports painful periods, deep pain during sex, pain with urination or bowel movements, painful rectal bleeding, blood in the urine, chronic fatigue, or difficulty getting pregnant. Less commonly recognized symptoms include shoulder tip pain, cyclical coughing or chest pain, and pain or swelling around surgical scars that follows a menstrual pattern.
Symptom diaries or tracking apps can help. While there’s no proof they speed up diagnosis on their own, guidelines note they help you document patterns and communicate clearly with your doctor, which can make a real difference when your symptoms are cyclical and easy to downplay in a single appointment.
The Pelvic Exam
During a pelvic exam, your doctor places one or two gloved fingers into the vagina (or sometimes the rectum) while pressing on your lower abdomen with the other hand. They’re feeling for nodules, hard lumps, or organs that seem stuck together or unusually tender. Deep endometriosis nodules and enlarged ovarian cysts can sometimes be felt this way.
The catch is that a normal pelvic exam does not rule out endometriosis. The diagnostic accuracy of a physical exam alone is low. ESHRE guidelines specifically state that even when the clinical exam is normal, further steps including imaging should still be pursued if symptoms are suggestive.
Ultrasound Imaging
Transvaginal ultrasound is the most accessible imaging tool and can identify certain types of endometriosis well, particularly ovarian endometriomas (blood-filled cysts on the ovaries, sometimes called “chocolate cysts”). It’s also increasingly used to detect deeper disease.
A structured approach published by the International Deep Endometriosis Analysis (IDEA) group outlines four steps for a thorough ultrasound exam. The sonographer evaluates the uterus and ovaries (including signs of adenomyosis), checks for “soft markers” like tenderness at specific spots and whether the ovaries move freely, performs a real-time “sliding sign” to see whether pelvic organs glide past each other normally (stuck organs suggest adhesions), and looks for deep nodules in both the front and back of the pelvis. Having a small amount of urine in the bladder during the scan helps identify nodules on the bladder wall.
The quality of an ultrasound depends heavily on the person performing it. A general pelvic ultrasound may miss endometriosis entirely, while a detailed scan by a specialist trained in the IDEA approach catches significantly more. If your ultrasound comes back “normal” but your symptoms persist, it’s worth asking whether the scan specifically looked for endometriosis.
MRI for Deeper Disease
MRI is particularly useful when deep infiltrating endometriosis is suspected, meaning tissue has grown into organs like the bowel, bladder, or the space between the uterus and rectum. For this type of disease, MRI has a sensitivity of about 90% and specificity of 91%, with an overall accuracy of 90%. For ovarian endometriotic cysts specifically, the accuracy climbs to 96%.
On MRI, endometriosis lesions typically appear as dark, dense nodules or areas of thickened tissue with irregular edges. Sometimes bright spots show up, indicating areas of bleeding within the tissue. The scan can also reveal indirect signs like a uterus pulled backward into a fixed position, organs tethered to each other by scar tissue, or fluid shifted out of its normal position by adhesions.
MRI is not always ordered as a first step. It’s most commonly used when ultrasound findings are inconclusive, when surgery is being planned and the surgical team needs a detailed map of disease location, or when disease in the bowel or urinary tract is suspected.
Laparoscopy: The Surgical Standard
Direct visualization and biopsy during laparoscopy remains the gold standard for a definitive diagnosis. During this minimally invasive surgery, a small camera is inserted through a tiny incision near the navel. The surgeon can see endometriosis lesions directly on pelvic surfaces and take tissue samples. A pathologist then examines the samples under a microscope to confirm the presence of endometrial-type tissue outside the uterus.
The advantage of laparoscopy is that it can both diagnose and treat in the same procedure. Surgeons often remove or destroy visible endometriosis during the diagnostic surgery rather than requiring a second operation later. This is also when staging happens. The revised American Society for Reproductive Medicine (rASRM) system assigns points based on the size, depth, and location of lesions and any adhesions found. The points add up to a stage: Stage I (minimal) is 1 to 5 points, Stage II (mild) is 6 to 15, Stage III (moderate) is 16 to 40, and Stage IV (severe) is above 40.
That said, not everyone needs surgery for a diagnosis. Current guidelines recognize that imaging combined with a trial of hormonal treatment (like birth control pills or progestins) is a reasonable alternative to jumping straight to laparoscopy. The pros and cons of each path should be weighed based on your symptoms, your goals (especially if fertility is a concern), and how much disease is suspected.
Saliva Tests: Not Ready for Routine Use
A saliva-based test called Endotest, developed by the company Ziwig, became commercially available in France in 2022. It works by analyzing a panel of 109 small RNA molecules in saliva that appear to form a distinct signature in people with endometriosis. Early studies in symptomatic patients reported sensitivity around 96% and specificity around 95%.
Those numbers sound promising, but the test was developed and studied only in symptomatic patients at specialized centers. A larger validation study of 1,000 people is underway in France, and an interim analysis of 200 participants has shown similar accuracy. Until broader validation is complete and the test is available outside of specialized settings, it is not part of standard diagnostic practice in most countries. No major international guideline currently recommends saliva or blood biomarker testing for endometriosis diagnosis.
What the Diagnostic Path Looks Like in Practice
For most people, diagnosis starts with a conversation about symptoms and a pelvic exam, followed by a transvaginal ultrasound. If endometriomas or deep nodules are found, the diagnosis may be considered confirmed enough to begin treatment without surgery. If the ultrasound is normal but symptoms are significant, MRI may be the next step. If imaging is inconclusive or if surgery would change the treatment plan, laparoscopy is offered.
The staging number you receive after surgery does not reliably predict how much pain you experience. Some people with Stage I disease have severe symptoms, while others with Stage IV have relatively few. Staging is more useful for describing the physical extent of disease, guiding surgical decisions, and assessing fertility impact than for measuring how “bad” the condition feels day to day.