Urobilinogen is a colorless substance formed in the intestines by bacterial action on bilirubin.
Bilirubin, formed from the metabolism of hemoglobin flows through the biliary tract into the small intestine. Bilirubin is transformed, as it is broken down through the action of bacteria, into urobilinogen.
Once formed, most of the urobilinogen is excreted in the feces, but a small amount will be reabsorbed in the intestines and pass into the bloodstream. It either goes to the liver again, where it is metabolized and excreted in bile, or eventually pass through the kidneys and it is excreted in the urine.
The daily urobilinogen excreted in the feces is approximately between 40 and 280 mg whereas the daily urobilinogen excreted into the urine is just 0.4 to 4 mg/day.
Urobilinogen level in the urine may be elevated because the liver is incapable of processing the recycled urobilinogen in the blood or because there are elevated levels of bilirubin present.There are tests to detect the amount of urobilinogen excreted in the feces as well as urobilinogen excreted in the urine.
The urinary urobilinogen test is an important tool in routine urinalysis since it serves as a guide in detecting and differentiating liver disease, hemolytic disease, and biliary obstruction.
A positive result of urobilinogen in the urine (urobilinogen positive +) is useful for diagnosis because it may be related to:
This test is performed along with other urine tests. The patient must collect a sample of the urine in a specific container using a special kit. This sample will be sent to the lab for the analysis.
Urobilinogen can be tested either with a dipstick or with a tablet that change of color (in about 30 to 60 seconds) in the presence of a high amount of urobilinogen in the urine.
In laboratories, there are automated machines that perform the analysis, but it is also possible to buy strips that let you analyze a urine sample at home. They comprise up to 10 or more different reagents or chemical pads to perform different urine tests at the same time.
The normal range for urobilinogen in the urine is between 0 and 1 mg/dl. If the values are in the normal range the test is considered negative.
The results may be slightly different depending on the method and the lab performing the test.
The presence of urobilinogen in the urine should be below 1 mg/dl to be considered negative. If the result is above 1 mg/dl is considered positive (+)
If the urobilinogen measured in the test is high, the urine has an orange/brown color because urobilinogen gets oxidized to urobilin.
The most common diseases related to a positive (+) result in an urobilinogen urine test are:
Some drugs may interfere causing a false positive result for urobilinogen in the urine:
Eating bananas may also produce a false positive.
The following values of urobilinogen in the urine are considered to be above the normal range:
IMPORTANT: These levels are expressed in mg/ml. They are an example of a healthy adult of about 45 years old with no known disease and not taking any medication. The ranges can be different depending on the laboratory or on your personal circumstances.
Urobilinogen | Situation | ||||||
|---|---|---|---|---|---|---|---|
| Mild urobilinogen increase | |||||||
| 1 mg/dl | 1.1 mg/dl | 1.2 mg/dl | 1.3 mg/dl | 1.4 mg/dl | 1.5 mg/dl | 1.6 mg/dl | 1.7 mg/dl |
| 1.8 mg/dl | 1.9 mg/dl | 2 mg/dl | 2.1 mg/dl | 2.2 mg/dl | 2.3 mg/dl | 2.4 mg/dl | 2.5 mg/dl |
| 2.6 mg/dl | 2.7 mg/dl | 2.8 mg/dl | 2.9 mg/dl | 3 mg/dl | 3.1 mg/dl | 3.2 mg/dl | 3.3 mg/dl |
| 3.4 mg/dl | 3.5 mg/dl | 3.6 mg/dl | 3.7 mg/dl | 3.8 mg/dl | 3.9 mg/dl | 4 mg/dl | |
| Moderate urobilinogen increase | |||||||
| 4.1 mg/dl | 4.2 mg/dl | 4.3 mg/dl | 4.4 mg/dl | 4.5 mg/dl | 4.6 mg/dl | 4.7 mg/dl | 4.8 mg/dl |
| 4.9 mg/dl | 5 mg/dl | 5.1 mg/dl | 5.2 mg/dl | 5.3 mg/dl | 5.4 mg/dl | 5.5 mg/dl | 5.6 mg/dl |
| 5.7 mg/dl | 5.8 mg/dl | 5.9 mg/dl | 6 mg/dl | 6.1 mg/dl | 6.2 mg/dl | 6.3 mg/dl | 6.4 mg/dl |
| 6.5 mg/dl | 6.6 mg/dl | 6.7 mg/dl | 6.8 mg/dl | 6.9 mg/dl | 7 mg/dl | 7.1 mg/dl | 7.2 mg/dl |
| 7.3 mg/dl | 7.4 mg/dl | 7.5 mg/dl | 7.6 mg/dl | 7.7 mg/dl | 7.8 mg/dl | 7.9 mg/dl | 8 mg/dl |
| Marked urobilinogen increase | |||||||
| 8.1 mg/dl | 8.2 mg/dl | 8.3 mg/dl | 8.4 mg/dl | 8.5 mg/dl | 8.6 mg/dl | 8.7 mg/dl | 8.8 mg/dl |
| 8.9 mg/dl | 9 mg/dl | 9.1 mg/dl | 9.2 mg/dl | 9.3 mg/dl | 9.4 mg/dl | 9.5 mg/dl | 9.6 mg/dl |
| 9.7 mg/dl | 9.8 mg/dl | 9.9 mg/dl | 10 mg/dl | 10.1 mg/dl | 10.2 mg/dl | 10.3 mg/dl | 10.4 mg/dl |
| 10.5 mg/dl | 10.6 mg/dl | 10.7 mg/dl | 10.8 mg/dl | 10.9 mg/dl | 11 mg/dl | 11.1 mg/dl | 11.2 mg/dl |
| 11.3 mg/dl | 11.4 mg/dl | 11.5 mg/dl | 11.6 mg/dl | 11.7 mg/dl | 11.8 mg/dl | 11.9 mg/dl | 12 mg/dl |
| Severe urobilinogen increase | |||||||
| 12.1 mg/dl | 12.2 mg/dl | 12.3 mg/dl | 12.4 mg/dl | 12.5 mg/dl | 12.6 mg/dl | 12.7 mg/dl | 12.8 mg/dl |
| 12.9 mg/dl | 13 mg/dl | 13.1 mg/dl | 13.2 mg/dl | 13.3 mg/dl | 13.4 mg/dl | 13.5 mg/dl | 13.6 mg/dl |
| 13.7 mg/dl | 13.8 mg/dl | 13.9 mg/dl | 14 mg/dl | ||||
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