Gynecologists use a combination of symptom review, physical exams, imaging, and sometimes surgery to check for endometriosis. There is no single quick test that confirms it, which is a major reason the average time from first symptoms to diagnosis is 7.5 to 10 years. The process typically moves from less invasive steps to more invasive ones, depending on what each round of evaluation reveals.
Symptom Review Comes First
Your gynecologist will start by asking detailed questions about your pain patterns. The symptoms that raise suspicion for endometriosis include severe period pain, deep pain during sex, pain with urination or bowel movements, painful rectal bleeding, fatigue, and difficulty getting pregnant. Some of these symptoms follow your menstrual cycle, but they don’t have to. Non-cyclical pelvic pain also counts.
European clinical guidelines recommend that clinicians consider an endometriosis diagnosis based on this symptom picture alone, even before any tests come back. That matters because it means your doctor should take your symptoms seriously as a starting point rather than waiting for imaging to “prove” something is wrong.
The Pelvic Exam
During a standard pelvic exam, your gynecologist will press on areas around the uterus and lower pelvis to check for tenderness. They’re also feeling for nodules or hard lumps, which can indicate endometriosis tissue growing in places it shouldn’t be.
For deeper growths, your doctor may perform a rectovaginal exam, placing one finger in the vagina and one in the rectum. This lets them feel for nodules in the tissue between the rectum and vagina, a common spot for deep endometriosis. When a painful nodule is found in this area, the positive predictive value for endometriosis is about 94%, meaning it’s a strong indicator. However, a normal pelvic exam doesn’t rule endometriosis out. The exam has limited ability to distinguish exactly which structures are involved, and smaller or superficial growths often can’t be felt at all. Guidelines recommend moving to imaging even when the physical exam is completely normal.
Ultrasound and the Sliding Sign
Transvaginal ultrasound is typically the first imaging step. The probe is inserted into the vagina, giving a close-up view of the uterus, ovaries, and surrounding structures. It’s particularly good at spotting endometriomas (cysts on the ovaries filled with old blood, sometimes called “chocolate cysts”) and nodules affecting the bladder wall, bowel, or ligaments behind the uterus. These nodules appear as dark, irregular masses on the screen.
One specific technique used during ultrasound is called the “sliding sign.” The examiner gently presses the ultrasound probe against the cervix while watching the screen to see whether the rectum glides smoothly over the back of the uterus and cervix. They may also press on your lower abdomen with their other hand to rock the uterus back and forth. If the bowel moves freely, the sign is positive, meaning that area is likely clear. If the bowel appears stuck and doesn’t slide, that suggests the tissue has become scarred or fused together by endometriosis, a condition called obliteration of the space between the uterus and rectum.
Ultrasound is very useful for deep and ovarian endometriosis, but it has a significant blind spot: it generally cannot detect superficial endometriosis, which are small, flat patches of tissue on the lining of the pelvis. A normal ultrasound does not mean you don’t have endometriosis.
MRI for a More Detailed Picture
MRI is often ordered when ultrasound results are unclear, when deep endometriosis is suspected in multiple locations, or when surgical planning requires a more complete map. It provides detailed images of soft tissue throughout the pelvis.
Overall, MRI detects deep infiltrating endometriosis with a sensitivity around 67% to 94% and a specificity around 77% to 85%, depending on how strictly the results are interpreted. It performs especially well for endometriosis involving the rectum, where specificity reaches roughly 98%. Like ultrasound, MRI struggles with superficial disease. It’s a helpful tool for confirming and mapping what’s there, but a clean MRI still doesn’t exclude the diagnosis.
Laparoscopy: The Surgical Option
Laparoscopy has long been considered the gold standard for confirming endometriosis. It’s a minimally invasive surgery performed under general anesthesia. Your surgeon makes small incisions in the abdomen, inserts a thin camera, and visually inspects the pelvic organs and surrounding tissue for endometriosis growths. If suspicious tissue is found, the surgeon takes a small biopsy and sends it to a lab for confirmation under a microscope.
That biopsy step is important. Surgeons correctly identify endometriosis by sight about 90% of the time, but they also overdiagnose it. In one validation study, surgeons visually diagnosed endometriosis in 82% of women, while lab analysis confirmed it in only 74%. The specificity of visual inspection alone was just 40%, meaning many things that look like endometriosis under the camera turn out to be something else. This is why guidelines recommend combining what the surgeon sees with tissue biopsy for a proper diagnosis.
Laparoscopy also allows treatment during the same procedure. If endometriosis is found, the surgeon can often remove or destroy the growths right then, so diagnosis and treatment happen in one step.
Surgery Isn’t Always Required
Current guidelines from the European Society of Human Reproduction and Embryology recognize that you don’t necessarily need surgery to start treatment. If your symptoms, exam, and imaging all point toward endometriosis, your gynecologist can make a clinical diagnosis and begin a trial of hormonal treatment, such as hormonal contraceptives or progestogen therapy. If your symptoms improve on this treatment, that response itself supports the diagnosis.
This approach has become more accepted because laparoscopy carries the risks of any surgery, including anesthesia, infection, and organ injury, and may not be the right first step for everyone. The decision between pursuing surgery or trying empirical treatment should be a conversation between you and your doctor, weighing the severity of your symptoms, your fertility goals, and how much diagnostic certainty you need.
Staging After Diagnosis
If endometriosis is confirmed surgically, it’s classified into four stages based on a point system that accounts for the number, size, and depth of growths, plus any scarring or adhesions. Stage I (1 to 5 points) is minimal disease, Stage II (6 to 15) is mild, Stage III (16 to 40) is moderate, and Stage IV (over 40 points) is severe. These stages describe the physical extent of the disease, but they don’t always correlate with pain. Someone with Stage I can have debilitating symptoms, while someone with Stage IV might have relatively little pain.
A Saliva Test on the Horizon
A saliva-based test called the Endotest, developed by Ziwig, analyzes tiny molecules in saliva to detect endometriosis. It has shown about 96% accuracy in studies and is currently available under France’s national reimbursement program for women aged 18 to 43 with chronic pelvic pain and inconclusive imaging. It’s prescribed in around 100 French hospitals. The test is not yet widely available outside France, but it represents a significant shift toward noninvasive diagnosis. If it gains broader regulatory approval, it could dramatically shorten the years-long diagnostic journey many patients currently face.