 Conversely, conjugated bilirubin is hydrophilic and thus can be detected as present in the urine — bilirubinuria — in contrast to unconjugated bilirubin which is absent in the urine.Medical imaging such as ultrasound, CT scan, and HIDA scans are useful for detecting bile duct blockage.Yellow discoloration of the skin, especially on the palms and the soles, but not of the sclera or inside the mouth is due to carotenemia—a harmless condition.