From the Guidelines
Laboratory testing for abdominal pain should be tailored to the clinical presentation, typically including complete blood count (CBC), comprehensive metabolic panel (CMP), urinalysis, and lipase, as these tests help identify infection, inflammation, and organ dysfunction, guiding further management and narrowing the differential diagnosis. The choice of laboratory tests is crucial in the workup of abdominal pain, as it can significantly impact patient outcomes in terms of morbidity, mortality, and quality of life. According to the most recent and highest quality study available, 1, a step-up approach for diagnosis from clinical and laboratory examination to imaging examination should be used, tailored to the hospital's resources.
Key Laboratory Tests
- Complete Blood Count (CBC): Helps identify infection or inflammation through elevated white blood cells.
- Comprehensive Metabolic Panel (CMP): Assesses liver and kidney function, electrolytes, and glucose levels.
- Urinalysis: Can detect urinary tract infections or kidney stones.
- Lipase: Essential for diagnosing pancreatitis.
Additional Tests
- Pregnancy test for women of childbearing age.
- Amylase for suspected pancreatitis.
- Lactate for ischemia concerns.
- C-reactive protein or erythrocyte sedimentation rate to assess inflammation.
- Stool studies may be warranted for diarrhea or suspected gastrointestinal infection.
- Blood cultures should be considered with fever or suspected sepsis, as indicated by 1.
Clinical Context
The specific combination of tests ordered should be guided by the patient's history, physical examination findings, and suspected diagnoses, with results interpreted in the clinical context rather than in isolation. This approach is supported by the World Journal of Emergency Surgery, 1, which emphasizes the importance of a step-up approach for diagnosis, incorporating clinical assessment, laboratory tests, and imaging as appropriate, to manage intra-abdominal infections effectively. By prioritizing these tests and considering the clinical context, healthcare providers can optimize the diagnostic workup for abdominal pain, ultimately improving patient outcomes.
From the Research
Laboratory Testing for Abdominal Pain
The workup for abdominal pain typically involves a combination of laboratory tests and imaging studies to narrow down the differential diagnosis. Some of the recommended laboratory 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, 3, 4
- Pregnancy testing 2
- Serum amylase 3, 4
Interpretation of Laboratory Results
It's essential to interpret laboratory results in the context of the patient's clinical presentation and other diagnostic findings. For example:
- Elevated serum lipase levels can be seen in various intra-abdominal inflammatory conditions, not just acute pancreatitis 3
- Serum amylase and lipase levels are not specific for pancreatitis and can be elevated in nonpancreatic conditions 3, 4
- A threshold concentration 2-4 times the upper limit of normal is recommended for the diagnosis of acute pancreatitis 4
Imaging Studies
Imaging studies are often used in conjunction with laboratory tests to diagnose the cause of abdominal pain. The choice of imaging study depends on the location of pain and the suspected etiology:
- Computed tomography (CT) with intravenous contrast media is often used for generalized abdominal pain, left upper quadrant pain, and lower abdominal pain 2
- Ultrasonography is the study of choice for right upper quadrant pain 2
- Point-of-care ultrasonography can aid in the prompt diagnosis of several etiologies of acute abdominal pain, including cholelithiasis, urolithiasis, and appendicitis 2