What substance causes jaundice when it builds up in the bloodstream?

Jaundice occurs when there is an accumulation of bilirubin in the bloodstream. Bilirubin is a yellow pigment that is produced during the normal breakdown of red blood cells. When hemoglobin from these cells is broken down, it is converted into bilirubin, which is then processed by the liver.

If the liver is unable to adequately process or excrete bilirubin due to liver diseases, bile duct obstructions, or conditions that lead to excessive breakdown of red blood cells (hemolysis), the bilirubin levels increase, resulting in the yellowing of the skin and eyes characteristic of jaundice.

Cholesterol and albumin do not contribute to jaundice in the same way bilirubin does. Cholesterol is a lipid important for cell membranes and hormone production, while albumin is a protein that helps maintain oncotic pressure in the blood. Hemoglobin, on the other hand, is the oxygen-carrying component of red blood cells, but it is bilirubin derived from hemoglobin that causes jaundice when elevated. Therefore, when discussing the causes of jaundice, bilirubin is the key substance involved.