Urine Urobilinogen Test: Normal Range & Causes

What Is Urine Urobilinogen?

Urobilinogen is a colourless by-product of bilirubin metabolism. After red blood cells are broken down, the liver processes bilirubin into bile, which enters the intestine. Gut bacteria then convert bilirubin into urobilinogen. Some urobilinogen is reabsorbed into the bloodstream and excreted by the kidneys into urine, giving urine its characteristic yellow colour.

Why Is This Test Ordered?

In my clinical practice, I often order a urine urobilinogen test when a patient presents with jaundice, dark urine, pale stools, or unexplained fatigue. It helps differentiate between causes of jaundice — pre-hepatic, hepatic, or post-hepatic (obstructive). The test is also part of a routine urinalysis and can screen for liver disease or haemolytic disorders.

Normal Reference Range

Normal urine urobilinogen levels are typically 0.1–1.0 mg/dL (or 1–4 Ehrlich units/L). Values can vary slightly between laboratories. The table below summarises general adult ranges.

Note: Concentrations >1.0 mg/dL are considered elevated; <0.1 mg/dL is abnormally low.

Interpreting High Levels

Is high urine urobilinogen dangerous?

Elevated urobilinogen suggests increased bilirubin production (haemolysis) or impaired liver function. Common causes include haemolytic anaemia, cirrhosis, hepatitis, or Gilbert's syndrome. In my experience, a mildly high reading with no other symptoms may be benign, but persistently high levels warrant further investigation.

Urobilinogen during pregnancy

Pregnancy can cause mild elevations due to hormonal changes and increased red cell turnover. However, significant rises may indicate pregnancy-related liver disorders such as intrahepatic cholestasis of pregnancy. If you're pregnant, always discuss results with your obstetrician.

Interpreting Low or Absent Levels

Low or absent urobilinogen points to a blockage in bile flow (obstructive jaundice) — for example, from gallstones, pancreatic tumours, or cholangitis. Other causes include severe liver failure or very dilute urine. Absent urobilinogen with bilirubinuria strongly suggests biliary obstruction.

Factors That Can Affect Results

• Hydration: Very dilute urine may falsely lower urobilinogen concentration.
• Medications: Tetracyclines, sulfonamides, and some anti-inflammatory drugs can reduce urine urobilinogen.
• Vitamin C (ascorbic acid): High doses may interfere with some test strips.
• Time of day: Levels peak in the afternoon (2–4 PM); morning samples are lower.

How Is the Test Performed?

A random urine sample is usually sufficient, though a 24-hour collection may be ordered in certain cases. The laboratory uses a dipstick test that reacts with urobilinogen to produce a colour change (Ehrlich reaction). Normal urine appears pale yellow; dark orange-red on the dipstick indicates high urobilinogen.

When to See a Doctor

If you notice persistently dark urine, yellowing of the skin or eyes, pale stools, or abdominal pain, consult a healthcare provider. A simple urine urobilinogen test, combined with blood bilirubin and liver enzymes, can quickly pinpoint the underlying issue.

LOINC Code: 20438-7 (Urobilinogen [Mass/volume] in Urine)