American Medical Technologist (AMT) Practice Exam

In a patient with jaundice, the serum appears yellow because of elevated levels of bilirubin. Bilirubin is a breakdown product of hemoglobin from red blood cells, and when its levels rise, it imparts a yellow color to the serum. This condition occurs when there is an excess of bilirubin in the bloodstream, which can happen due to various reasons such as liver dysfunction, bile duct obstruction, or increased hemolysis of red blood cells.

While pale yellow could be a color of normal serum, in the context of jaundice, the notable increase in bilirubin concentration leads to a more pronounced yellow coloring of the serum. Red serum typically indicates the presence of hemolysis or another blood component that is not related to the jaundice itself. Green serum may be observed in certain rare conditions, but it is not a characteristic manifestation of jaundice. Therefore, the yellow color is the key indicator in cases of elevated bilirubin and is textbook evidence of the condition.