What happens to indirect bilirubin when liver cells are damaged?

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The key idea is that bilirubin must be conjugated in the liver to be excreted. Indirect (unconjugated) bilirubin is the form before conjugation. When liver cells are damaged, the uptake and the conjugation process (UDP-glucuronosyltransferase activity) are impaired, so unconjugated bilirubin cannot be efficiently converted to the conjugated, water-soluble form. As a result, indirect bilirubin accumulates in the blood, so its level rises. It does not become water-soluble due to the damage, and the problem isn’t that conjugation is happening more rapidly.