How Diverticulitis Is Diagnosed

Diverticulitis is a condition that must be diagnosed by a physician, even for those in whom it has been a problem in the past. In most cases, a careful medical history and an abdominal computed tomography (CT) scan is going to be the typical way that diverticulitis is diagnosed.

diverticulitis diagnosis
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Self-Checks/At-Home Testing

There is no way to diagnose diverticulitis at home. Even if it’s already known that diverticula are present because they were found during a colonoscopy or other test, or even if diverticulitis has been diagnosed in the past, patients are not able to diagnose and treat this condition themselves.

When severe or persistent symptoms of abdominal pain, fever, constipation, diarrhea, nausea, or vomiting occur, it’s necessary to see a physician as soon as possible (even in the emergency department if symptoms are severe).


A CT scan, which is also sometimes called a computerized tomography scan, is the test used when diverticulitis is suspected. A CT scan is a type of x-ray but instead of one flat image, it provides a series of images that show a cross-sectional view of the body. An abdominal CT scan can show the organs and tissues of the digestive tract, including the large intestine, where colonic diverticula are located.

What to Expect

In preparation for a CT scan, patients will be asked to stop eating about four hours prior to the exam and to drink only water. Oral, IV, and sometimes rectal contrast are used with a CT scan when diverticulitis is suspected. Patients will be asked to drink a solution containing barium. The barium will pass through the digestive tract and help to illuminate structures inside the body on the CT scan images.

Contrast may also be given rectally, through the use of an enema. Finally, there will be IV contrast. All of these types of contrast will help the health professional see if there are any diverticula in the large intestine and visualize other organs in order to make the diagnosis of diverticulitis.

A CT scanner is a large machine that has a round opening in the middle. Patients will lie on a table that slides into the opening in the machine during the test. The mechanism in the scanner that takes the x-rays will rotate around to take the images. It’s necessary to stay still during the test and at points, the radiology technician will give instructions to hold your breath.

When IV contrast is used, an IV will be started to administer it. The test itself is not uncomfortable, but there can be discomfort associated with receiving an IV and an enema for contrast.

Drinking contrast can also be challenging for some patients, which can be made somewhat easier if the contrast is cold and if you drink it through a straw.


A colonoscopy is usually recommended a few months after the diverticulitis has been treated successfully. This test is not used to diagnose diverticulitis and will not be done while the diverticulitis is active due to potential complications.

In rare cases, it’s not clear from the abdominal CT scan if the diagnosis is truly diverticulitis or if colorectal cancer or another condition could also be present. A colonoscopy can be used to ensure both that the diverticulitis has resolved and that there are no other conditions present in the colon.

A follow-up colonoscopy and any other tests that might be needed will be individualized based on the patient’s situation and on physician preference.

Diverticulitis Doctor Discussion Guide

Get our printable guide for your next doctor's appointment to help you ask the right questions.

Doctor Discussion Guide Woman

Differential Diagnoses

Abdominal pain is associated with various other conditions, which is why it’s necessary to get an accurate diagnosis of diverticulitis before treatment starts. In addition, more than one condition can occur in the digestive tract at the same time, making it vital to find any other reasons for the pain or other digestive symptoms such as diarrhea, constipation, or vomiting. Some of the differential diagnoses for diverticulitis include:

  • Appendicitis: An inflammation of the appendix is a common condition which also causes left-sided abdominal pain. Appendicitis is often considered alongside diverticulitis and is another reason a physician might order a CT scan. 
  • Colon cancer: A mass inside of the colon could cause some symptoms similar to diverticulitis.
  • Ovarian cancer: Cancer in the ovaries can also cause abdominal pain and a change in bowel habits.
  • Inflammatory bowel disease (IBD): Crohn’s disease and ulcerative colitis, which are chronic conditions of the digestive system, may also cause abdominal pain and other symptoms inside and outside the digestive tract. 

Frequently Asked Questions

  • What is the pain of diverticulitis like?

    Diverticulitis pain is usually severe and persistent. It is sometimes accompanied by fever, constipation, diarrhea, nausea, or vomiting, and should be seen by a doctor. 

  • Can a CT scan detect diverticulitis?

    Yes, a CT scan is the test used to diagnose diverticulitis. Sometimes a contrast CT is required, which involves drinking a barium solution that helps to illuminate intestinal structures. 

  • What conditions present similarly to diverticulitis?

    Conditions with similar symptoms to diverticulitis include appendicitis, colon cancer, ovarian cancer, and inflammatory bowel disease. 

11 Sources
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
  1. Linzay CD, Pandit S. Acute Diverticulitis. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing. Available from:

  2. Rezapour M, Ali S, Stollman N. Diverticular Disease: An Update on Pathogenesis and ManagementGut Liver. 2018;12(2):125–132. doi:10.5009/gnl16552

  3. Destigter KK, Keating DP. Imaging update: acute colonic diverticulitisClin Colon Rectal Surg. 2009;22(3):147–155. doi:10.1055/s-0029-1236158

  4. Snyder MJ. Imaging of colonic diverticular diseaseClin Colon Rectal Surg. 2004;17(3):155–162. doi:10.1055/s-2004-832696

  5. Johnson CD, Baker ME, Rice RP, Silverman P, Thompson WM. Diagnosis of acute colonic diverticulitis: comparison of barium enema and CT. AJR Am J Roentgenol; 148(3):541-6.

  6. Ou G, Rosenfeld G, Brown J, et al. Colonoscopy after CT-diagnosed acute diverticulitis: Is it really necessary?Can J Surg. 2015;58(4):226–231. doi:10.1503/cjs.014514

  7. Lembcke B. Diagnosis, Differential Diagnoses, and Classification of Diverticular DiseaseViszeralmedizin. 2015;31(2):95–102. doi:10.1159/000380833

  8. Harvey J, Roberts PL, Schoetz DJ, et al. Do Appendicitis and Diverticulitis Share a Common Pathological Link?. Dis Colon Rectum; 59(7):656-61.

  9. Huang WY, Lin CC, Jen YM, et al. Association between colonic diverticular disease and colorectal cancer: a nationwide population-based study. Clin Gastroenterol Hepatol; 12(8):1288-94.

  10. Metz Y, Nagler J. Diverticulitis presenting as a tubo-ovarian abscess with subsequent colon perforationWorld J Gastrointest Surg. 2011;3(5):70–72. doi:10.4240/wjgs.v3.i5.70

  11. Peppercorn MA. The overlap of inflammatory bowel disease and diverticular disease. J Clin Gastroenterol; 38(5 Suppl 1):S8-10.

Additional Reading
  • Baum JA. "Colonic Diverticulitis.” Merck Manual Professional Edition.  

  • Ramirez PT, Gershenson DM, Gershenson DM, Salvo G. "Ovarian Cancer.” Merck Manual Professional Edition.

By Amber J. Tresca
Amber J. Tresca is a freelance writer and speaker who covers digestive conditions, including IBD. She was diagnosed with ulcerative colitis at age 16.