Laboratory Tests for Suspected Cholangitis
For patients with suspected acute cholangitis, order the following laboratory tests: complete blood count with differential, C-reactive protein, comprehensive metabolic panel including total and direct bilirubin, alkaline phosphatase, aminotransferases (ALT/AST), albumin, and prothrombin time. 1, 2
Essential Laboratory Markers
Inflammatory Markers
- White blood cell count (WBC) - typically shows leukocytosis indicating systemic infection 1, 3, 2
- C-reactive protein (CRP) - levels >75 mg/L support the diagnosis of acute cholangitis 1
- These markers help distinguish infectious cholangitis from other causes of biliary obstruction 1, 2
Cholestatic Markers
- Alkaline phosphatase (ALP) - the most common biochemical abnormality in cholangitis, typically elevated 1, 4
- Total and direct bilirubin - elevation >2× upper limit of normal indicates biliary stasis; fractionation helps confirm hepatobiliary origin 5, 1, 2
- Gamma-glutamyltransferase (GGT) - confirms hepatobiliary origin of elevated ALP 5
- Aminotransferases (ALT/AST) - typically elevated but less prominently than ALP 1, 2
Hepatic Synthetic Function
- Albumin - assesses hepatic synthetic function and helps with risk stratification 5
- Prothrombin time/INR - evaluates coagulation status and liver function 5
- Platelet count - important for risk assessment and may indicate advanced liver disease 5
Clinical Context and Pitfalls
The combination of fever/chills, right upper quadrant pain, and jaundice (Charcot's triad) is now seen less frequently than historically described, particularly in patients with indwelling biliary tubes or after biliary manipulation 3, 2. However, laboratory abnormalities remain consistently present 3, 4.
Important caveat: Patients with indwelling biliary tubes may develop cholangitis without significant jaundice, making inflammatory markers (WBC, CRP) particularly important in this population 3.
Additional Considerations for Specific Scenarios
When Sclerosing Cholangitis is in the Differential
- Serum IgG4 levels - should be tested at screening to identify IgG4-related cholangitis 5
- Antinuclear antibody (ANA) and anti-smooth muscle antibody - establish baseline to evaluate for overlap syndrome with autoimmune hepatitis 5
- IgG levels - elevated in autoimmune hepatitis overlap 5
For Severity Grading
Laboratory markers help classify cholangitis severity according to Tokyo Guidelines: severe (Grade III) cholangitis includes organ dysfunction markers such as creatinine >2.0 mg/dL (renal dysfunction) or evidence of cardiovascular dysfunction requiring vasopressors 1, 2.
Diagnostic Algorithm Integration
These laboratory tests should be obtained alongside abdominal ultrasound as the initial imaging modality 1, 6. The diagnosis requires clinical signs (fever, abdominal pain, jaundice), laboratory findings indicating inflammation and biliary stasis, and imaging evidence of biliary dilatation or obstruction 1, 2.