A 65-year-old woman is admitted with RUQ pain radiating to the right shoulder, accompanied by nausea and vomiting. Examination reveals tenderness in the RUQ and a positive Murphy's sign. A diagnosis of acute cholecystitis is made. What is the most likely finding?
A
Serum bilirubin levels may be elevated.
B
Cholelithiasis is present in 40-60%.
C
Bacteria are rarely found at operation.
D
An elevated amylase level excludes this diagnosis.