From the Guidelines
For a patient presenting with abdominal pain, the most appropriate diagnostic tests to order are those that follow a stepwise approach, starting with less invasive and more readily available tests, such as complete blood count, comprehensive metabolic panel, urinalysis, and lipase/amylase, before proceeding to imaging studies like abdominal X-rays, ultrasound, and CT scan with contrast, as recommended by the American College of Radiology and supported by studies such as 1 and 1. The selection of tests should be guided by the patient's history, physical examination findings, and evolving clinical picture. Initial tests typically include:
- Complete blood count to assess for infection or inflammation
- Comprehensive metabolic panel to evaluate liver and kidney function
- Urinalysis to rule out urinary tract infections
- Lipase/amylase to check for pancreatitis Imaging studies are often necessary, starting with:
- Abdominal X-rays to detect obstruction or perforation
- Ultrasound which is particularly useful for gallbladder disease, appendicitis, or gynecological conditions
- CT scan with contrast provides detailed evaluation of most abdominal pathologies and is the gold standard for many conditions Additional tests like:
- Pregnancy test for women of childbearing age
- Stool studies for suspected infectious diarrhea
- Lactate levels for suspected ischemia should be considered based on clinical suspicion, as suggested by studies such as 1, 1, and 1. It is essential to note that the diagnosis of intra-abdominal infections is mainly clinical, and early detection and treatment are crucial to minimize complications, as emphasized by 1 and 1. A step-up approach for diagnosis, tailored to the clinical setting and resources, is recommended, beginning with clinical and laboratory examination and progressing to imaging examinations, as stated in 1 and 1.
From the Research
Diagnostic Tests for Abdominal Pain
The following diagnostic tests are recommended for a patient presenting with abdominal pain:
- Complete blood count (CBC) 2, 3, 4
- C-reactive protein (CRP) 2
- Hepatobiliary markers 2
- Electrolytes 2
- Creatinine 2
- Glucose 2
- Urinalysis 2, 5
- Lipase 2
- Pregnancy testing 2
Imaging Studies
Imaging studies are chosen based on the location of pain and index of suspicion for specific etiologies:
- 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
- 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
Disease-Specific Diagnostic Tests
Certain diseases require specific diagnostic tests:
- Acute appendicitis: CT or ultrasonography 2, 6
- Cholecystitis: ultrasonography 2, 6
- Urolithiasis: urinalysis, CT or ultrasonography 2, 6
- Diverticulitis: CT or ultrasonography 2, 6
- Upper gastrointestinal bleeding: complete blood count, basic metabolic panel, coagulation panel, liver tests, and type and crossmatch 4