 Testing urine for both bilirubin and urobilinogen can help differentiate obstructive liver disease from other causes of jaundice.Bilirubin was discovered by Rudolf Virchow in 1847.It is not always distinguished from hematoidin, which one modern dictionary defines as synonymous with it but another defines as "apparently chemically identical with bilirubin but with a different site of origin, formed locally in the tissues from hemoglobin, particularly under conditions of reduced oxygen tension."