<prompt> A 64-year-old man complains of abdominal pain, pruritus, 4-lb weight loss, and anorexia. There are multiple scratch marks on the skin of the extremities and flank. The bilirubin is 1.0 mgdL. To determine if the condition is due to cholestasis, blood should be tested for which of the following?Direct and indirect bilirubinAlkaline phosphataseSerum glutamic-oxaloacetic transaminase SGOTSerum glutamic-pyruvic transaminase SGPT  <response>: Pruritus occurs frequently in untreated obstructive jaundice. Bile salt elevation is a possible cause of pruritus. Patients with generalized pruritus should have alkaline phosphatase levels determined; if levels are elevated, the possibility of cholestatic jaundice should be considered. Bilirubin is not always elevated in obstructive jaundice. 