Urobilinogen in Urine

What is Urobilinogen in Urine?

bilirubin. The metabolism is takes place at intestine with the assistance of intestinal bacteria. In normal condition, maximum urobilinogen is excreted through fecal material and small quantity is reabsorbed and stored in liver to recycle the urobilinogen for further bile production. Very small quality of urobilinogen in urine excreted.

Image 1: Process of Urobilinogen in urine

Unconjugated bilirubin is never present in urine, as they tightly bound with serum protein (albumin) and in excessive bounded form raised the unconjugated bilirubin level in serum. Bounded unconjugated bilirubin cannot filter via kidney and does not reach to the urine.

Causes

The different pathophysological conditions are associated with urobilinogen in urine, which include:

• Hepatic diseases and cholestic diseases
• Pancreatic conditions which leads to obstruction in the flow of bile and leads to jaundice
• Dubin-Johnson syndrome is a metabolic disorder of bilirubin which causes increased level of conjugated bilirubin due to 10q24 chromosomal defect which causes weaken emission of conjugated bilirubin and other non-bile salt.
•  Rotor’s syndrome is a rare syndrome associated with mutilation of flow of organic anions from hepatic cells into the canalicular lumen. This leads to faulty secretion of conjugated bilirubin, its re-absorption into the blood and excretion in the urine.
• Gilbert’s syndrome is an inherited genetic disorder which occurs due to the anomaly of the gene responsible for glucuronyltransferase. This leads to inability of hepatic conjugation of the bilirubin due to impaired liver function.
• Haemolysis is the condition when bone marrow unable to maintain the balance of production of RBCs in comparison with their destruction rate. Haemolysis may occur due to genetic disorder or may be due to a disorder in immune system.
• Post viral hepatitis is also caused of urobilinogen in urine. Different types of hepatitis viruses which include hepatitis A- E.
• Mild chronic hepatitis in the condition where the liver inflammatory condition is stayed for prolonged periods (more than 6 months). This may occur may be due to hepatitis, toxic drug ingestion or autoimmunity.
• Crigler-Najjar syndrome is congenital disorder associated with abnormal bilirubin metabolism. This occurs due to lack of uridine-diphosphate glycosyltransferase enzyme which assists in conjugation reaction.

Test Procedure

For testing the urobilinogen in urine, multi-reagent dip strip is available, but do cautiously with proper instruction, otherwise it will provide faulty result.

• Check the expiry date of the package of the strips
• Take one clean sterilized urine collection container
• Collect the fresh urine into the container
• Take out a strip carefully
• Dip the strip into the urine sample
• Take out the strip
• Wait for the specific time written in the instruction note
• Notice the colour change
• Make a comparison between the colour changed in the strip and the colour chart provided on the strip bottle.

• Image 2: Urine test procedure

Normal Values

The normal value of the urobilinogen in Urine is less than 1mg/dl (<17 umol/l).  The measuring ranged used for urobilinogen in urine detection is 0 – 8 mg/dl.

Clinical Significance

In the normal individual very minute quantity of urobilinogen is present in the urine. In pathogenic condition, conjugated bilirubin can only present in urine. Increased level of urobinolinogen indicates the following conditions, such as,

Image 3: Clinical significance of Urobilinogen in urine

• Ruptured of red blood cell (haemolysis), this may associate with pregnancy related factors.
• pernicious anaemia
• Hepatic disease
• Hepatic infection
• Hepatic cancer
• Liver cirrhosis
• Increase level of hepatic enzymes
• Increased production of urobilinogen
• Decrease platelet count
• Urobinolinogen in urine clinically indicates jaundice
• Poisoning

False positive results of urobilinogen in urine can obtain in the following conditions:

• Increased nitrate level from the normal value
• Contaminated urine with stool
• Using of phenazopyridine dye for detecting Urinary tract infections.
• Drug contamination which includes chlorpromazine and selenium.
• Sample is not freshly collected

Decreased level of urobilinogen in urine

• Presence of calculi in the bile duct, which block the common bile duct
• Cholestasis also causes intra or extra bile duct obstruction leads to slow flow of bile from liver to small intestine.
• Decrease bile production in urine

False negative test results of urobilinogen in urine can obtain in the following conditions:

• Extended period of exposure of the urine sample in light
• Urine sample is collected long period back
• Patient has taken Rifampicin and vitamin C

References

1. Urobilinogen in urine: Normal & Abnormal values at http://www.anytestkits.com/urobilinogen.htm
2. http://www.drugcheck.com/hc_uc-hs_urobilinogen.html
3. http://www.medscape.com/viewarticle/763579_4
4. http://patient.info/doctor/bilirubinuria
5. What Affects the Test & What To Think About at http://www.webmd.com/a-to-z-guides/urine-test?page=4