Patients suspected of having choledocholithiasis are diagnosed with a combination of laboratory tests and imaging studies. The first imaging study obtained is typically a transabdominal ultrasound. The results of laboratory testing and transabdominal ultrasound are then used to stratify a patient as high risk, intermediate risk, or low risk for having choledocholithiasis.
•High-risk
Patients with any one of the following are considered at high risk for a CBD stone and have an estimated probability of having a CBD stone of >50 percent:
The presence of a CBD stone on transabdominal ultrasound or cross-sectional imaging.
Acute cholangitis.
A serum bilirubin greater than 4 mg/dL (68 micromol/L) and a dilated CBD on ultrasound (more than 6 mm in a patient with a gallbladder in situ and more than 8 mm in those that have had a cholecystectomy).
•Intermediate risk
Patients with any one of the following are considered to be at intermediate risk with an estimated 10 to 50 percent probability of having a CBD stone:
Abnormal liver biochemical tests.
Age >55.
Dilated CBD on ultrasound or cross-sectional imaging.
