Bile pigments
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Normally, bilirubin is present in freshly voided urine. On standing, it is converted into biliverdin (green colour), bilicyanine (blue) and cholestelin (violet, red, reddish yellow).
- Iodine ring test
- A sensitive cum reliable test
- Layer a solution of 10% alcoholic iodine on urine in a test tube
- A green colour indicates presence of bile
- Harrison test
- A sensitive test
- To 5 ml of urine add 5 ml of 10% barium chloride in a test tube
- Shake and filter it off
- Let the filter paper dry
- Then add 1-2 drops of Fouchet’s reagent
- A green colour indicates bilirubinuria
- Gmelin’s test
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Bile pigments are oxidized by acids to coloured derivatives.
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Take 2 ml of concentrated nitric acid in a test tube
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Add 2 ml of urine along the side of the test tube
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At the junction of the two fluids, a play of colour – green, blue, violet etc. will be observed if bile pigment is present
Interpretation
- Moderate to severe hepatocellular damage
- Obstruction of bile ducts, extrahepatic or intrahepatic
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In early hepatocellular damage and haemolysis urine bilirubin may be negative.
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Last modified: Monday, 25 October 2010, 11:17 AM