Physicians trying to determine the cause of a patient’s abdominal pain will typically first obtain the patient’s medical history and perform a physical examination.

Sometimes it may be difficult to make a diagnosis, causing the patient frustration. Patients should be prepared to describe the pain and answer a number of other questions. They may be asked to complete a pain assessment.

Physicians may begin their evaluation by asking about the exact location of the pain. Although the presence of a large number of organs can make it difficult to pinpoint the cause of abdominal pain, determining the location of the pain can help shorten the list.

Pain in different areas of the abdomen can suggest a number of causes, including:

In addition to asking the patient about the location of their abdominal pain, physicians may ask a number of other questions, including:

• Is the pain focused in a specific location or all over (generalized or diffuse)?
  
• Is it severe, sharp or cramping? Constant or periodic?
  
• Does it change intensity?
  
• How often does the pain occur?
  
• Is it worsening?
  
• Has there been an injury recently?
  
• Are any other symptoms occurring at the same time (e.g., fever, vomiting)?
  
• Does the pain cause insomnia or awakening at night?
  
• Does it increase in times of stress?
  
• Has similar pain occurred in the past? If so, how long have the episodes lasted?
  
• How does food or drink affect the pain?
  
• Does the pain increase after straining efforts?
  
• Does sexual activity, urination, defecation or menstruation affect it?
  
• Is pregnancy a factor?
  
• Does the pain radiate to the back, shoulder blade, groin, buttocks or legs?
  
• Does it change when lying on the back or belly or side?
  
• What medications are being taken?
  
• Is there a family history of bowel disorders?

In addition, women may be asked about their menstrual history and use of contraception. Women and men may be asked about their sexual history. This will help physicians determine if certain conditions, such as ectopic pregnancy, pelvic inflammatory disease or sexually transmitted diseases, should be ruled out. In some cases, a pregnancy test will be ordered.

During the physical examination, physicians will try to determine if the pain is localized or diffuse. The physician will take the patient's vital signs to look for changes in blood pressure and heart rate. The patient’s temperature may also be taken to determine if fever is present. In addition, the physician may examine the eyes and skin for signs of jaundice, the lungs for signs of consolidation (filling of the airways with liquid or tissue) and the heart for murmurs and rubs (sounds caused by friction).

Physicians will examine the abdomen visually and possibly listen for bowel sounds. They may also touch (palpate) the abdomen to look for masses and localized tenderness. Rectal examinations may be performed on men with prostate pain and on patients with acute abdominal pain, and pelvic exams may be performed on women with acute lower abdominal pain. Patients may also be examined for hernia and signs of nerve and muscle wall injury.

In addition to the medical history and physical examination, there are a number of tests commonly used to identify and rule out conditions that may be causing abdominal pain. These include:

• Blood tests. These tests determine the amount of any given substance in a blood sample. Blood tests commonly performed to evaluate abdominal pain include complete blood count (CBC), liver tests (e.g., liver enzyme tests, bilirubin) and tests of pancreatic enzymes (e.g., amylase and lipase).
  
  
• Urine tests. These tests involve physically or visually examining a urine sample. During an evaluation of abdominal pain, urine may be checked for blood or infection.
  
  
• Stool tests. These tests examine the stool for evidence of a number of conditions. During an evaluation of abdominal pain, stool may be checked for blood, infection or worm infestation.
  
  
• Ultrasound of the abdomen. This procedure uses high-frequency sound waves to create images of organs and other body structures.
  
  
• X-rays of the abdomen. An x-ray is a painless test in which an image is created of part of the body. It uses low doses of electromagnetic radiation that are reflected on film or fluorescent screens.
  
  
• CAT scan (computed axial tomography). Used to outline small structures or pathology in the abdomen. It is extensively used to rule out appendicitis in suspicious cases. It is also used to diagnose urinary stones.
  
  
• Endoscopy of the upper gastrointestinal (GI) tract (upper endoscopy). A tiny camera mounted on a flexible tube (endoscope) is inserted through the mouth and down the throat. This allows the physician to inspect the esophagus, stomach, and the upper portion of the small intestine. This brief procedure, once conducted in physicians' offices, is now generally performed in a hospital with the patient under anesthesia. When necessary, small instruments can be used to collect tissue samples through the endoscope for a biopsy or to burn the bleeding sites. Upper endoscopy is also known as an esophagogastroduodenoscopy (EGD).
  
  
• Colonoscopy. In simple terms, colonoscopy is an endoscopy of the lower GI tract. A tiny camera mounted on a flexible tube is inserted through the rectum. This allows physician to inspect the rectum and colon. It can also be used to take tissue sample for biopsy and to burn the bleeding sites.
  
  
• Capsule endoscopy.  This is a newer procedure in which the patient swallows a camera, which is usually in the form of a capsule. The camera takes the pictures and can transmit them to a computer.  It is mainly used to inspect the small intestine where it cannot be reached with traditional endoscope. 
  
  
• Upper GI (gastrointestinal) and small bowel series. This procedure requires the patient to swallow a barium-containing liquid. A set of x-rays are then taken to examine the esophagus, stomach, and small intestine.
  
  
• Barium enema. A barium-containing liquid (and in some cases air) is introduced into the rectum and colon (also known as the large intestine). The procedure is used to improve the images made by an x-ray. This enables a physician to detect changes or abnormalities in the colon.
  

In some cases, laparoscopy is required to examine the abdominal cavity and pinpoint the cause of abdominal pain. A small incision is made above or below the navel. A thin lighted tube (laparoscope) is then inserted into the abdomen. This enables physicians to view the abdominal organs.