What should you know about dark urine after blood transfusion?

Dark yellow urine can occur when you have not been drinking normally or have lost fluid through fever, sweating, vomiting, or diarrhoea. Red, brown, or cola-coloured urine after transfusion can also contain blood pigment released when red blood cells break down. A reaction may occur during the transfusion or later, and possible clues include fever, chills, back or chest pain, breathlessness, nausea, dizziness, fast heartbeat, yellowing, or a sudden fall in urine output. Hepatitis A or hepatitis B are separate liver-related possibilities when dark urine accompanies yellowing and pale stools, though colour alone cannot identify the cause.

Contact the transfusion service, hospital, or treating clinician immediately and say when the transfusion ended, when the colour changed, and what other symptoms you have. If you are still in a healthcare setting, tell staff at once. Do not wait for the next appointment, drive yourself if faint or breathless, or take someone else’s medicine. Keep your discharge papers and medication list available. A clinician may check urine, blood counts, kidney function, and markers of red-cell breakdown.

Call emergency services for breathing difficulty, chest pain, collapse, confusion, severe weakness, intense back pain, rapidly worsening fever or chills, or inability to pass urine. Urgent assessment is needed for any red or cola-coloured urine after transfusion, especially with yellowing, dizziness, or reduced urine.

Ask whether the transfusion record has been reviewed, which tests are needed for a reaction, and what symptoms should prompt immediate return to hospital.