Ovarian cysts are most commonly diagnosed with a pelvic ultrasound, which can confirm a cyst exists, pinpoint its location, and show whether it’s filled with fluid or solid material. In many cases, cysts are discovered incidentally during a routine pelvic exam or an imaging scan done for another reason. From there, your doctor uses a combination of physical examination, imaging, and sometimes blood tests to determine what type of cyst you have and whether it needs treatment.
The Pelvic Exam: Where It Often Starts
Many ovarian cysts are first suspected during a routine pelvic exam. Your doctor may feel a swelling on or near an ovary during the manual part of the exam. A pelvic exam alone can’t tell you what kind of cyst it is or whether it’s concerning, but it’s often what prompts the next step: imaging.
Some cysts cause symptoms that lead you to the doctor in the first place. A dull or sharp ache in the lower abdomen, pain during certain activities, or sudden severe pain on one side can all point toward an ovarian cyst. Larger cysts sometimes cause the ovary to twist, producing pain that comes and goes or starts suddenly. Cysts that rupture or bleed can cause intense, acute pain. These symptoms don’t confirm a cyst on their own, but they give your doctor important context before ordering a scan.
Pelvic Ultrasound: The Primary Diagnostic Tool
Ultrasound is the first-line imaging test for ovarian cysts. A wand-shaped device called a transducer sends high-frequency sound waves to create a real-time image of your uterus and ovaries on a screen. Most often, this is done transvaginally (the transducer is inserted into the vagina), which provides a closer, clearer view of the ovaries than an abdominal ultrasound.
The ultrasound image tells your doctor several things at once. It confirms that a cyst is present, shows exactly where it sits, and reveals its internal structure. A simple cyst, one that’s entirely filled with fluid and has thin, smooth walls, is almost always benign. A complex cyst may have thicker walls, internal dividers (called septations), or solid areas mixed in with fluid. These features don’t automatically mean cancer, but they do signal that the cyst needs closer evaluation.
Ultrasound also measures the cyst’s size, which matters for deciding next steps. Small, simple cysts often resolve on their own within a few menstrual cycles. Your doctor may recommend a follow-up ultrasound in 6 to 8 weeks to check whether the cyst has shrunk, stayed the same, or grown.
When an MRI Is Needed
About 22% to 24% of ovarian masses remain indeterminate after ultrasound, meaning the scan couldn’t clearly classify them as benign or concerning. When that happens, MRI is the most useful next step. MRI provides much more detailed soft-tissue contrast than ultrasound, which helps distinguish between different types of tissue inside the cyst.
Your doctor may also recommend an MRI if the cyst is larger than 10 centimeters, if your body type or surrounding organs make it difficult for ultrasound to get a clear picture, or if it’s unclear whether the mass is coming from the ovary or a nearby structure. For pregnant patients who can’t be fully evaluated with ultrasound, a noncontrast MRI (without the injectable dye) is the preferred alternative.
MRI can also be used during surveillance. If a cyst that looked indeterminate on ultrasound is being monitored over time, a contrast-enhanced MRI can detect suspicious changes in appearance that ultrasound might miss.
Blood Tests and the CA-125 Marker
In some cases, your doctor will order a blood test called CA-125. This protein is found at higher levels in the blood of many people with ovarian cancer, and levels above 35 units per milliliter are generally considered irregular. An elevated CA-125 combined with concerning ultrasound features and physical exam findings raises the suspicion for ovarian cancer, particularly in people who have already gone through menopause.
CA-125 is not a standalone cancer test, though. Plenty of non-cancerous conditions raise CA-125 levels, including menstruation, pregnancy, endometriosis, pelvic inflammatory disease, uterine fibroids, and liver disease. In premenopausal people, CA-125 results are especially hard to interpret because so many common conditions can skew the number. That’s why doctors always read this result alongside imaging findings and clinical history rather than in isolation.
Pregnancy Tests and Hormone Panels
A pregnancy test is a routine part of the workup when an ovarian cyst is found in someone of reproductive age. A positive result changes the diagnostic picture significantly, because certain cysts (like corpus luteum cysts) are a normal part of early pregnancy and don’t require intervention. Knowing pregnancy status also determines which imaging and treatment options are safe.
In some situations, your doctor may check hormone levels to help identify the type of cyst. Functional cysts, the most common kind, are related to the normal hormonal cycle of ovulation. Hormone testing can help distinguish these from other types, such as endometriomas (cysts filled with old blood, associated with endometriosis) or dermoid cysts (which contain a mix of tissue types like hair, fat, and skin cells).
Surgical Diagnosis: Laparoscopy
Surgery is rarely the first step in diagnosing an ovarian cyst, but it becomes necessary when imaging and blood tests can’t rule out a serious problem. Laparoscopy is a minimally invasive procedure where a small camera is inserted through a tiny incision near your navel, allowing the surgeon to directly view the ovary and cyst.
During laparoscopy, the surgeon can remove the cyst and send it to a lab for examination under a microscope, which gives a definitive diagnosis. This is typically recommended when a cyst has suspicious features on imaging, when CA-125 is elevated in a postmenopausal person, when a cyst is large or growing, or when it’s causing significant symptoms like persistent pain or ovarian torsion. In most cases, if the cyst turns out to be benign, removal during the same procedure is the only treatment needed.
What Happens After Diagnosis
The diagnostic path you follow depends heavily on your age, symptoms, and what the cyst looks like on imaging. A small, simple, fluid-filled cyst in a premenopausal person is so common and so unlikely to be harmful that watchful waiting with a repeat ultrasound is the standard approach. Many of these cysts disappear without any treatment.
Complex cysts, large cysts, cysts in postmenopausal people, or cysts paired with elevated CA-125 levels get a more thorough workup. Your doctor may move from ultrasound to MRI to blood work in a stepwise fashion, each test narrowing down the possibilities. The goal at every stage is the same: to figure out whether the cyst is something your body will handle on its own or something that needs to be removed and examined.