Which of the following is a known characteristic of bilirubin?

Bilirubin is a yellow compound that results from the breakdown of red blood cells and is primarily processed by the liver. A key characteristic of bilirubin is its sensitivity to light exposure, leading to rapid oxidation. When exposed to light, bilirubin can undergo photochemical reactions that convert it into water-soluble products, which is why phototherapy is used in the treatment of neonatal jaundice. This property highlights its instability under light conditions, making it crucial for laboratories to handle bilirubin samples away from light to preserve their integrity for accurate measurement.

The other choices do not align with the established properties of bilirubin. For instance, bilirubin is not soluble in water, which is a characteristic of its structure; it requires certain conditions or chemical modifications to become soluble. Additionally, while bilirubin can generally be stable under certain controlled conditions, it is not inherently stable due to its susceptibility to light and oxidation. Lastly, bilirubin has significant implications for liver function, as elevated levels can indicate liver dysfunction or biliary obstruction, contradicting the assertion that it has no significant impact. Understanding these characteristics is essential for accurate diagnostics and treatment strategies in clinical chemistry.