In a patient with right upper quadrant pain and dark brown urine, which laboratory test should be checked?

• A. LFTs
• B. CBC
• C. TSH
• D. Lipase

Answer: (A)

LFTs assess hepatobiliary function and injury, which is precisely what RUQ pain with dark urine often signals. Dark brown urine suggests bilirubin excretion in the urine, typically from elevated conjugated (direct) bilirubin due to liver dysfunction or biliary obstruction. A complete liver function test panel—including AST/ALT for hepatocellular injury, alkaline phosphatase and GGT for cholestasis, and total/direct bilirubin—helps determine whether the problem is hepatocellular damage, biliary obstruction, or another liver process. It also provides a jaundice assessment and helps gauge severity.

CBC might help identify infection or anemia but doesn’t specifically evaluate liver/biliary function. TSH isn’t relevant to jaundice or RUQ pain. Lipase targets pancreatic inflammation, which isn’t the primary concern suggested by dark urine in this scenario.