From the Guidelines
Bilirubinuria workup should begin with a comprehensive history and physical examination, followed by laboratory tests including complete blood count, liver function tests (ALT, AST, alkaline phosphatase, GGT), total and direct bilirubin levels, and urinalysis, as bilirubinuria indicates conjugated hyperbilirubinemia, which suggests either hepatocellular damage or biliary obstruction preventing normal bilirubin excretion into the intestine. The initial evaluation should focus on differentiating between obstructive and non-obstructive causes of jaundice, with a right upper quadrant US being the usual initial imaging evaluation to confirm an obstructive process and localize the site of obstruction 1. Additional tests such as MRCP or ERCP may be necessary if obstruction is suspected, and viral hepatitis serologies, autoimmune markers, and ceruloplasmin levels should be considered based on clinical suspicion 1. In cases of hemolysis, additional tests like haptoglobin, LDH, and peripheral blood smear are warranted. The presence of bilirubinuria always indicates pathology requiring investigation, and a detailed history, targeted physical examination, and pertinent laboratory studies are essential for differentiating between the various potential etiologies of jaundice 1. Key considerations in the workup include:
- Laboratory tests to evaluate liver function and bilirubin levels
- Imaging studies such as US, MRCP, or ERCP to evaluate the liver, gallbladder, and biliary tract
- Viral hepatitis serologies and autoimmune markers to evaluate for infectious and autoimmune causes
- Ceruloplasmin levels to evaluate for Wilson's disease
- Tests for hemolysis, such as haptoglobin, LDH, and peripheral blood smear, if suspected. Given the most recent and highest quality study available, the workup for bilirubinuria should prioritize a comprehensive history and physical examination, followed by targeted laboratory tests and imaging studies to evaluate for obstructive and non-obstructive causes of jaundice 1.
From the Research
Workup for Bilirubinuria
The workup for bilirubinuria, which is the presence of bilirubin in the urine, typically involves a series of tests to determine the underlying cause of the condition.
- The initial evaluation should include a careful history and physical examination, followed by laboratory tests such as fractionated bilirubin, complete blood count, alanine transaminase, aspartate transaminase, alkaline phosphatase, γ-glutamyltransferase, prothrombin time and/or international normalized ratio, albumin, and protein 2.
- Imaging studies such as ultrasonography or computed tomography may be used to differentiate between extrahepatic obstructive and intrahepatic parenchymal disorders 2.
- The presence of bilirubin in the urine can be an indicator of significant underlying disease, such as liver disease or bile duct obstruction 3, 2.
- The evaluation of patients with jaundice, which is a physical finding associated with hyperbilirubinemia, starts with a careful history and physical examination, followed by directed imaging of the biliary tree and liver 3.
Laboratory Tests
- Laboratory tests such as elevated bilirubin, alanine transaminase, aspartate transaminase, and alkaline phosphatase can be used to evaluate patients with jaundice and bilirubinuria 2, 4.
- The sensitivity and specificity of these tests can vary, and a combination of tests may be needed to determine the underlying cause of the condition 4.
Imaging Studies
- Ultrasonography is a useful imaging modality for evaluating patients with jaundice and bilirubinuria, and can help to differentiate between extrahepatic obstructive and intrahepatic parenchymal disorders 2, 4.
- Computed tomography can also be used to evaluate patients with jaundice and bilirubinuria, and can provide additional information about the underlying cause of the condition 2.