The cause for hyperbilirubinemia in a patient may not be immediately obvious. A battery of simple tests can often identify the probable pathologic process.
Processes that can explain hyperbilirubinemia:
(1) hemolysis
(2) hepatocellular disease
(3) biliary obstruction
Screening tests:
(1) urobilinogen
(2) urine conjugated bilirubin
(3) urine hemoglobin
(4) fecal color
(5) indirect bilirubin level
(6) ratio of direct to total bilirubin
(7) serum alkaline phosphatase
(8) serum ALT
Test
Hemolysis
Hepatocellular
Obstructive
urobilinogen
usually increased, may be normal
negative to increased
negative
urine conjugated bilirubin
normal
increased
increased
urine hemoglobin
positive
negative
negative
fecal color
dark brown
normal to pale
pale to white
indirect bilirubin level
increased
variable
normal
ratio of direct to total bilirubin
< 20%
20 - 60%
> 50%
serum alkaline phosphatase
normal
normal to 2 times ULN
> 2 times ULN
serum ALT
normal
> 2 times ULN
normal to 2 times ULN
Limitations:
• This assumes that only 1 process is occurring and no confounding processes are present.
• These findings assume moderate to severe disease. However, mild disease might not cause hyperbilirubinemia.
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