Urinalysis - The Carter Center

characteristic color with the other color pigments (urochroms).
Urobilinogen is also converted into urobilin when exposed to air.
Stercobilinogen in the intestine is either eliminated from the body
unchanged or oxidized to the colored compound stercobilin, which gives
the faces its characteristic color. Thus, urine normally contains only a
very small amount of urobilinogen and no bilirubin. Both are abnormal
urinary constituents. However, there are several serious conditions in
which either one or both of these substances are found in the urine.
When testing for urobilinogen the urine specimen must be fresh, since it
is usually unstable and it is rapidly oxidized to urobilin. This oxidation
takes place so readily that most urine specimens that contain
urobilinogen will show an abnormal color caused by partial oxidation of
urobilin. The presence of urobilinogen and that of urobilin have the same
clinical significance, however, they take part in different chemical
reactions, and urine is more frequently tested for urobilinogen.
Normal value: Normally 1-4 mg of urobilinogen is excreted in the urine
each day.
Clinical Significance
Urine is often tested for increases in urobilinogen when investigating
hemolytic jaundice or liver disorder in which liver function is
impaired.
Test for Urobilinogen
A. Qualitative Ehrlich's Test for Urobilinogen
Principle
The test depends upon the reaction between urobilinogen and paradimethylaminobenzaldhyde
to form a cherry (deep) red.
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