From the Guidelines
For suspected acute cholecystitis, I recommend drawing a complete blood count (CBC), comprehensive metabolic panel (CMP), liver function tests (LFTs), lipase, and C-reactive protein (CRP) or erythrocyte sedimentation rate (ESR). The CBC may show leukocytosis with left shift, indicating inflammation or infection. The CMP evaluates kidney function and electrolytes, while LFTs (including ALT, AST, alkaline phosphatase, bilirubin, and GGT) can reveal biliary obstruction or liver involvement. Elevated lipase helps rule out pancreatitis, which can present similarly. Inflammatory markers like CRP or ESR are often elevated in acute cholecystitis. Blood cultures should be obtained if sepsis is suspected. These laboratory tests complement clinical assessment and imaging studies like ultrasound, but they aren't diagnostic on their own. The pattern of abnormalities helps distinguish cholecystitis from other conditions like choledocholithiasis or cholangitis, which may show more significant elevations in bilirubin and transaminases. While laboratory abnormalities support the diagnosis, normal lab values don't exclude acute cholecystitis, as some patients may have minimal laboratory derangements despite significant inflammation.
Key Laboratory Tests
- Complete blood count (CBC) with differential leukocyte count and platelet count
- Comprehensive metabolic panel (CMP) to evaluate kidney function and electrolytes
- Liver function tests (LFTs) including ALT, AST, alkaline phosphatase, bilirubin, and GGT
- Lipase to rule out pancreatitis
- C-reactive protein (CRP) or erythrocyte sedimentation rate (ESR) as inflammatory markers
- Blood cultures if sepsis is suspected, as recommended by 1 and 1
Imaging Studies
Imaging studies like ultrasound are crucial in diagnosing acute cholecystitis, as noted in 1 and 1. However, the choice of imaging modality may depend on the clinical presentation and suspicion of complications. For non-pregnant adults with suspected acute cholecystitis, if both US and CT are equivocal/nondiagnostic and clinical suspicion persists, the panel suggests obtaining either an abdominal MRI/MRCP or HIDA scan as subsequent imaging to diagnose acute cholecystitis, as recommended by 1.
Clinical Considerations
The diagnosis of acute cholecystitis should be based on a combination of clinical signs, laboratory findings, and imaging results. The pattern of abnormalities helps distinguish cholecystitis from other conditions like choledocholithiasis or cholangitis. While laboratory abnormalities support the diagnosis, normal lab values don't exclude acute cholecystitis, as some patients may have minimal laboratory derangements despite significant inflammation, as noted in 1 and 1.
From the Research
Laboratory Tests for Suspected Acute Cholecystitis
The following laboratory tests are indicated for suspected acute cholecystitis:
- White blood cell count 2
- C-reactive protein level 2
- Liver function tests, including:
- Abnormal liver function tests, such as elevated liver enzymes, can be associated with acute cholecystitis 5
Diagnostic Criteria
Patients exhibiting one of the local signs of inflammation, such as Murphy's sign, or a mass, pain or tenderness in the right upper quadrant, as well as one of the systemic signs of inflammation, such as fever, elevated white blood cell count, and elevated C-reactive protein level, are diagnosed as having acute cholecystitis 2.
Combination of Tests
A combination of clinical, radiologic, and laboratory tests are needed to accurately diagnose or exclude acute cholecystitis 5. The diagnosis of acute cholecystitis was 100% correct in patients when the clinical diagnosis, ultrasound, and abnormal liver function test suggested the diagnosis of acute cholecystitis 5.