A 40 year old woman presents to the emergency depament with severe abdominal pain localized to the right upper quadrant. A urine sample is taken for rapid dipstick reagent strip analysis. A positive result for which of the following substances would most strongly suggest gallstone disease as a possible cause of her abdominal pain?

A small gallstone passing into the common bile duct can cause obstructive jaundice with conjugated hyperbilirubinemia. The conjugated bilirubin will spill into the urine, causing the bilirubin square on the reagent strip to react. This strip may also react with other causes of intrahepatic or extrahepatic obstructive jaundice, so it is not completely specific. It is woh becoming very familiar with the strengths and weaknesses of reagent strip technology, however, since this information may be available hours before serum chemistry values are repoed. High glucose in urine suggests diabetes mellitus. High nitrite in urine suggests urinary tract infection. High protein in urine suggests renal disease or myeloma. Ref: Kaplan M.M. (2012). Chapter 42. Jaundice. In D.L. Longo, A.S. Fauci, D.L. Kasper, S.L. Hauser, J.L. Jameson, J. Loscalzo (Eds), Harrison's Principles of Internal Medicine, 18e.