What is Urobilinogen?

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Infections or presence of pus cells in the liver or even in urine are indicative of grave body infections and hence immediate tests are recommended by the doctors. Failure to take these recommended tests can prove fatal as liver is directly associated with urine and our excretory system. Urobilinogen test  is one such test which finds out any defects and faults present in the liver or its operations.


What is Urobilinogen?

Urobilinogen is a water soluble and transparent product that is the by product of bilirubin reduction performed by the interstinal bacteria. It is formed by the breakdown of hemoglobin. While half of Urobilinogen circulates back to the liver, the other half is excreted through feces as urobilin. When ever there is hepatic damage, excess of it gets excreted out through the kidneys. This cycle is known as the enterohepatic urobilinogen cycle. There can be various factors that can hinder this cycle. One of the reasons being excess breakdown of hemoglobin(hemolysis) due to various liver malfunctions such as hepatitis, cirrhosis. When this happens, more Urobilinogen is produced and excreted in the urine. When a person has jaundice, it  is diagnosed by the color of the skin which is slightly yellow and the yellow color of the urine. However when there is an obstruction in the bile ducts, it will lead to a reduction in the amount of Urobilinogen and there is less amount of urobilin in the urine. Lower amount sof Urobilin can be due to a loss of the intestinal bacterial flora which are instrumental in synthesizing htis product. 

To detect the type of damage in the  liver, urobilinogen tests are conducted by measuring uribilinogen levels in the urine. Ehrlich Aldehyde Reaction is a common test that is used to test Urobilinogen levels. A benzaldehyde in the presence of acid changes the color if urobilinogen is present to pinkish red color. Altered or the complete absence of urobilinogen levels usually indicates a dysfunction of Liver. And increase in the level of urine urobilinogen hints towards red blood cells Hemolysis. The main purpose of this test is to help find out extra hepatic obstructions like common bile duct blockage and also to enable hepatic as well as hematologic disorders.



What are the different Urobilinogen levels in the Urine?

  • In urine :  the normal urobilinogen range is less than 17 umol/l (< 1mg/dl). The measuring urobilinogen range is 0 - 8 mg/dl. Abnormal urobilinogen values may display increased as well as low values.
  • Increased values are indicative of RBC breakdown in excess, liver overburdening, excess urobilinogen production, liver functioning in restriction, hematoma, poisoning, liver cirrhosis, hepatic function.
  • The low values are indicative of blockage in bileducts and bile production failure.




What are the characteristics of Urobilinogen test strips?

The test makes use of aminobenzaldehyde which is known to strongly react in acidic conditions with Urobilinogin. This reaction produces pink color.

  • When is it Normal  : The pink color indicates less than 17 umol/l (1mg/dl) urobilinogen which is considered as normal. 
  • When is it Negative : When the result is negative, it does not represent urobilinogen absence. The test patch appears obscured in color sometimes owing to the presence of p-aminosalicylic acid and sulphonamides in high concentrations. Some components like Nitrite, isonicotinic acid (INH) and indole display very less or almost no effect on this test.
  • Reagents used in this test : In this whole process, the active reagents are aminobenzaldehyde (0, 17% w/w); sulfosalicylic acid (40,0% w/w).
  • Range of Detection : The range of detection is 3 umol/l urobilinogen.



What are the points to consider prior to taking the  Urobilinogen test?

It is  difficult for most people to take such tests as they are afraid of the results, specially in cases of diagnosing for  liver problems. But the severity and influence of liver damage should be kept in mind and if the test is suggested it is a diagnostic tool for the doctor to figure out any problems with the liver. It need not always be that there is an absolute Liver problem. This test helps the doctors to diagnose the biliary tract and liver functioning. It is mandatory, that one should not take any fluids or food excluding bananas for atleast 48 hours before the test. The patient being tested should collect urine samples every 2 hours.



How does the Urobilinogen test help?

This test mostly helps in analyzing the urine for glucose, ketones, proteins, urobilinogen, pH, blood, nitrite, leucocytes, biliurbin and also Specificgravity.



What are the interfering factors in Urobilinogen test?

Some of the interfering factors which affect urobilinogen tests are sending the urine specimen instantly to the laboratory without observing pretest restrictions and possible decrease in phenazopyridine, procaine, sulfonamides, para-aminosalicylic acid, and phenothiazines.



Additional Reading on Diagnostic tests, click on the links below:

Heparin Flush

PET Scan



CAT Scan

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