This is a medical question of type : exams and tests 
 How to diagnose Diverticular Disease ? 
 Diverticulosis
                
Health care providers often find diverticulosis during a routine x ray or a colonoscopy, a test used to look inside the rectum and entire colon to screen for colon cancer or polyps or to evaluate the source of rectal bleeding.
                
Diverticular Disease
                
Based on symptoms and severity of illness, a person may be evaluated and diagnosed by a primary care physician, an emergency department physician, a surgeon, or a gastroenterologista doctor who specializes in digestive diseases.
                
The health care provider will ask about the persons health, symptoms, bowel habits, diet, and medications, and will perform a physical exam, which may include a rectal exam. A rectal exam is performed in the health care providers office; anesthesia is not needed. To perform the exam, the health care provider asks the person to bend over a table or lie on one side while holding the knees close to the chest. The health care provider slides a gloved, lubricated finger into the rectum. The exam is used to check for pain, bleeding, or a blockage in the intestine.
                
The health care provider may schedule one or more of the following tests:
                
- Blood test. A blood test involves drawing a persons blood at a health care providers office, a commercial facility, or a hospital and sending the sample to a lab for analysis. The blood test can show the presence of inflammation or anemiaa condition in which red blood cells are fewer or smaller than normal, which prevents the bodys cells from getting enough oxygen.  - Computerized tomography (CT) scan. A CT scan of the colon is the most common test used to diagnose diverticular disease. CT scans use a combination of x rays and computer technology to create three-dimensional (3D) images. For a CT scan, the person may be given a solution to drink and an injection of a special dye, called contrast medium. CT scans require the person to lie on a table that slides into a tunnel-shaped device where the x rays are taken. The procedure is performed in an outpatient center or a hospital by an x-ray technician, and the images are interpreted by a radiologista doctor who specializes in medical imaging. Anesthesia is not needed. CT scans can detect diverticulosis and confirm the diagnosis of diverticulitis.  - Lower gastrointestinal (GI) series. A lower GI series is an x-ray exam that is used to look at the large intestine. The test is performed at a hospital or an outpatient center by an x-ray technician, and the images are interpreted by a radiologist. Anesthesia is not needed. The health care provider may provide written bowel prep instructions to follow at home before the test. The person may be asked to follow a clear liquid diet for 1 to 3 days before the procedure. A laxative or enema may be used before the test. A laxative is medication that loosens stool and increases bowel movements. An enema involves flushing water or laxative into the rectum using a special squirt bottle. These medications cause diarrhea, so the person should stay close to a bathroom during the bowel prep.   - For the test, the person will lie on a table while the radiologist inserts a flexible tube into the persons anus. The colon is filled with barium, making signs of diverticular disease show up more clearly on x rays.  - For several days, traces of barium in the large intestine can cause stools to be white or light colored. Enemas and repeated bowel movements may cause anal soreness. A health care provider will provide specific instructions about eating and drinking after the test.  - Colonoscopy. The test is performed at a hospital or an outpatient center by a gastroenterologist. Before the test, the persons health care provider will provide written bowel prep instructions to follow at home. The person may need to follow a clear liquid diet for 1 to 3 days before the test. The person may also need to take laxatives and enemas the evening before the test.  - In most cases, light anesthesia, and possibly pain medication, helps people relax for the test. The person will lie on a table while the gastroenterologist inserts a flexible tube into the anus. A small camera on the tube sends a video image of the intestinal lining to a computer screen. The test can show diverticulosis and diverticular disease.  - Cramping or bloating may occur during the first hour after the test. Driving is not permitted for 24 hours after the test to allow the anesthesia time to wear off. Before the appointment, people should make plans for a ride home. Full recovery is expected by the next day, and people should be able to go back to their normal diet.