From the Guidelines
After a negative abdominal ultrasound, a CT scan of the abdomen and pelvis with IV contrast is usually the most appropriate next step to evaluate for a broad range of pathologies, as recommended by the American College of Radiology 1. This approach is supported by the ACR Appropriateness Criteria for acute nonlocalized abdominal pain, which suggests that CT of the abdomen and pelvis with IV contrast is usually appropriate to evaluate for abdominal abscesses and a broad range of additional pathologies 1. Some key points to consider when deciding on the next diagnostic test include:
- The patient's specific symptoms, medical history, and physical examination findings
- The clinician's suspicion regarding the underlying cause of pain
- The potential benefits and limitations of each diagnostic test
- The use of CT without IV contrast or MRI as alternative options in certain situations 1 Other diagnostic tests that may be considered after a negative abdominal ultrasound include:
- MRI of the abdomen and pelvis without and with IV contrast to provide clinically useful information in certain clinical settings 1
- Laboratory tests, such as complete blood count, liver function tests, pancreatic enzymes, and inflammatory markers, to provide valuable diagnostic information
- Endoscopic procedures, such as upper endoscopy or colonoscopy, to allow direct visualization of the GI tract and tissue sampling
- HIDA scans to assess gallbladder function
- Endoscopic ultrasound to combine endoscopy with ultrasound for detailed imaging of the pancreas and bile ducts
- Transvaginal ultrasound for gynecological concerns, which may offer better visualization than abdominal ultrasound 1
From the Research
Diagnostic Tests for Abdominal Pain
After a negative abdominal ultrasound, several other diagnostic tests can be considered to evaluate abdominal pain. These tests include:
- Complete blood count (CBC) 2
- C-reactive protein (CRP) 2
- Hepatobiliary markers 2
- Electrolytes 2
- Creatinine 2
- Glucose 2
- Urinalysis 2
- Lipase 2
- Pregnancy testing 2
Imaging Studies
Imaging studies can be chosen based on the location of pain and index of suspicion for specific etiologies. These include:
- Computed tomography (CT) with intravenous contrast media for generalized abdominal pain, left upper quadrant pain, and lower abdominal pain 2
- Ultrasonography for right upper quadrant pain 2, 3
- Point-of-care ultrasonography to aid in the prompt diagnosis of several etiologies of acute abdominal pain, including cholelithiasis, urolithiasis, and appendicitis 2
- Magnetic resonance imaging (MRI) in pregnant patients if ultrasonography results are inconclusive 2
Other Considerations
In patients with female reproductive organs, diagnoses such as ectopic pregnancy, pelvic inflammatory disease, and adnexal torsion should be considered 2. Extra-abdominal causes of abdominal pain, such as respiratory infections and abdominal wall pain, should also be considered 2, 4.
Specific Conditions
For certain conditions, specific diagnostic tests can be used, such as:
- Computed tomography with angiography (CTA) for diagnosis of ruptured abdominal aortic aneurysm (rAAA) 5
- Point-of-care ultrasound (PoCUS) for diagnosis of AAA 5
- Urine cytology and prostate-specific antigen (PSA) testing for diagnosis of urological malignancies and abdominal aortic aneurysms in patients with lower urinary tract symptoms 6