Why does hepatitis B cause dark urine?

Bilirubin is a yellow pigment produced as old red blood cells are broken down. A healthy liver processes it and sends it into bile. When hepatitis B inflames or injures liver cells, bilirubin can build up in the blood and be filtered into urine, making it look tea- or cola-coloured. Dark Urine is a common presentation of Hepatitis B. However, dark urine can also follow dehydration, foods, medicines, muscle injury, or other liver and bile conditions, so the colour alone cannot establish the cause.

Make a note of when the colour change began and whether you have yellow eyes or skin, pale stools, nausea, itching, fever, abdominal pain, or fatigue. Drink fluids normally, but do not assume a persistent colour change is only dehydration. Avoid alcohol until you have been assessed. A clinician can review your symptoms, medicines, possible exposures, and blood or urine tests to find the reason.

Seek prompt medical care for dark urine with jaundice, pale stools, abdominal pain, vomiting, fever, or a known hepatitis exposure. Get urgent help if you have confusion, severe drowsiness, fainting, vomiting blood, black stools, bleeding, or you are passing very little urine. These symptoms require urgent assessment even when hepatitis B has not been diagnosed.

Ask what may be causing the urine colour, whether liver and hepatitis tests are needed, whether any current medicines or supplements should be stopped, and which symptoms mean you should seek urgent care.