31.5 Clinical Significance...............................
Normally small amount of urobilinogen is excreted through urine (1–3.5 mg/24 h
urine). In hemolytic jaundice, urobilinogen is raised but not high because the liver is
not able to completely excrete the increased quantity and absorbed in the intestine.
So, in hemolytic jaundice, positive test for urobilinogen and urobilin is obtained with
negative test for bilirubin. In extrahepatic (obstructive) jaundice, the complete
absence of bilirubin in the intestine results in the absence of urobilinogen in urine.
In liver cirrhosis, in spite of the reduced amount of urobilinogen found in the
intestine, there is often an appreciable increase in urine urobilinogen which may
be of diagnostic value; as in these cases, bilirubin may not be present in the urine.
Pink color is also given by porphobilirubin and is of significance in porphyrias. It
may be distinguished from urobilinogen by the absence of color intensification on
addition of sodium acetate.
31.5 Clinical Significance 127