PID is a serious infection of the reproductive organs. Although an ultrasound can be used to detect PID, it isn’t always necessary for diagnosis. Less costly diagnostic tools are preferred.

To diagnose PID, a healthcare professional will typically start by performing an external exam, says Monte Swarup, MD, OB-GYN, founder of the health information site HPV HUB.

Next, they’ll perform an internal vaginal exam and take a sample of the cells for testing. They may swab the inside of the vaginal canal as well as the cervix.

If the results are inconclusive, they may move on to diagnostic procedures such as an ultrasound.

Ultrasounds aren’t the most common way to diagnose PID, says Michael Ingber, MD, urologist and female pelvic medicine specialist at The Center for Specialized Women’s Health in New Jersey.

An ultrasound will only reveal PID if it has progressed to the point where there are abscesses, adhesions, or scarring in the fallopian tubes, explains Dr. Jill Purdie, a board certified OB-GYN and medical director at Pediatrix Medical Group in Atlanta, Georgia.

Transvaginal ultrasound

A transvaginal ultrasound, which involves inserting an ultrasound probe into the vagina, can provide a clear image of the internal reproductive organs.

Your healthcare professional may be able to see abnormalities in the uterus, ovaries, fallopian tubes, cervix, and overall pelvic area that may be related to PID, explains Purdie.

CT scan

A CT scan can take X-ray images of your insides from a wide variety of angles. A healthcare professional might use a CT scan to check for abscesses or fluid buildup in the pelvis, says Purdie.

“Though, typically, a provider will issue an ultrasound over a CT scan if looking for PID specifically,” she says. Why? Because CT scans can expose reproductive organs to ionizing radiation.

MRI scans

An MRI uses magnets and radio waves to create snapshots of nearly every structure and organ inside the body.

In a 2017 review, researchers found that MRI could detect the following changes associated with PID:

While an MRI is more expensive than other imaging options, research suggests it is more sensitive and able to detect ovarian involvement in advanced PID cases.

Pelvic exam

Your healthcare professional will look for visible symptoms associated with PID, such as:

Swab test

Your healthcare professional will likely take cultures of the vagina with a super long Q-tip (called a swab) during an internal pelvic exam. This can be used to look for the presence of bacteria that might cause PID, says Purdie.

A swab test may also rule out other conditions, including yeast infections, bacterial vaginosis, and certain sexually transmitted infections.

Although a swab test can be used to confirm a PID diagnosis, it can’t be used to rule one out. It’s possible to have a negative swab test and still have PID.

Urine or blood test

A urine or blood test may be used to test for gonorrhea and chlamydia — the two leading causes of PID. Your healthcare professional may also recommend screening for other STIs at the same time.

A blood test may also be used to check your white blood cell count. This may offer insight into the likelihood of an infection somewhere in the body.

Ultrasound can be used to diagnose PID. However, healthcare professionals usually start with a pelvic exam and various labs — including swab, blood, and urine tests — before escalating to imaging tests.

Gabrielle Kassel (she/her) is a queer sex educator and wellness journalist who is committed to helping people feel the best they can in their bodies. In addition to Healthline, her work has appeared in publications such as Shape, Cosmopolitan, Well+Good, Health, Self, Women’s Health, Greatist, and more! In her free time, Gabrielle can be found coaching CrossFit, reviewing pleasure products, hiking with her border collie, or recording episodes of the podcast she co-hosts called Bad In Bed. Follow her on Instagram @Gabriellekassel.