What is the role of lab studies in the diagnosis of cholecystitis?

Updated: Jan 18, 2017
  • Author: Peter A D Steel, MBBS, MA; Chief Editor: Barry E Brenner, MD, PhD, FACEP  more...
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White blood cell (WBC) counts and measurements of aspirate aminotransferase (AST), alanine aminotransferase (ALT), bilirubin, and alkaline phosphate (ALP) may be helpful in the diagnosis of cholecystitis. However, because biliary obstruction is limited to the gallbladder in uncomplicated cholecystitis, elevation in the serum total bilirubin and ALP concentrations may not be present. Thus, the presence of normal values does not exclude cholecystitis.

A study by Singer et al examined the utility of laboratory values in acute cholecystitis diagnosed by hepatic 2,6-dimethyliminodiacetic acid (HIDA) scanning. [12] No difference was found in mean WBC counts and levels of AST, ALT, bilirubin, and ALP between patients diagnosed with cholecystitis and those without.

Mild elevation of amylase up to 3 times normal may be found in cholecystitis, especially when gangrene is present. A very high bilirubin should prompt the physician to pay special attention to the common bile duct and pancreatic region.

A comprehensive metabolic panel with bicarbonate may exhibit the following:

  • AST, ALT, and ALP levels may be elevated; however, as with other laboratory tests, these levels are not sensitive for excluding cholecystitis. When the AST and ALT levels are elevated significantly, a common bile duct stone is more likely.

  • An elevation of AST, ALT, or ALP measurements should raise the possibility of other biliary system pathology such as cholangitis, choledocholithiasis, or the Mirizzi syndrome.

  • Note the calcium level (Ranson criteria) if evidence of biliary pancreatitis exists.

  • Other abnormalities (eg, renal insufficiency) are not related to cholecystitis but may indicate a comorbid condition.

An elevated WBC is expected but not reliable. In a retrospective study, only 61% of patients with cholecystitis had a WBC count greater than 11,000 cells/µL. A WBC greater than 15,000 cells/µL may indicate perforation or gangrene.

Prothrombin time (PT) and activated partial thromboplastin time (aPTT) are not expected to be elevated unless sepsis or underlying cirrhosis is present. Coagulation profiles are helpful if the patient needs operative intervention.

For febrile patients, send 2 sets of blood cultures to attempt to isolate the organism in the presence of bacteremia from bacterial superinfection.

Although expected to be normal, urinalysis is essential in the workup of patients with abdominal pain to exclude pyelonephritis and renal calculi.

Conduct a pregnancy test for women of childbearing age.

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