Bilirubin
Definition
A yellow-orange breakdown product of biliverdin, seen as the yellow-brown phase of a resolving bruise. Its appearance indicates advancing haemoglobin degradation.
- Origin
- Breakdown product of biliverdin
- Colour
- Yellow-orange
- Bruise phase
- Later, resolving stage
- Indicates
- Advancing haemoglobin degradation
Common questions
Why is bilirubin's appearance used to estimate bruise age?+
Because it forms only after biliverdin has already broken down further, its presence signals that the bruise has progressed past its earliest stages, giving a rough marker of elapsed time since injury.
How reliable is bruise colour alone for dating an injury?+
It is widely regarded as unreliable for precise age estimation because the colour sequence varies with skin tone, bruise depth, individual healing rate, and lighting conditions, so it should be treated as indicative rather than a fixed timeline.
Related terms
- Biliverdin
- A green breakdown product of haemoglobin, appearing as the blue-green phase of bruise colour change. Biliverdin is then converted to bilirubin.
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