Question

Jaundice can first be visibly noted at what bilirubin level?

A) 0.5 mg/dL
B) 1.0 mg/dL
C) 2.0 mg/dL
D) 3.0 mg/dL

Answer 1

Jaundice becomes visible when the bilirubin level reaches around 2.0 mg/dL, at which point bilirubin exceeds its solubility and starts to discolor tissues yellow.

Step-by-step explanation:

Jaundice, also known as icterus, can first be visibly noted when the serum bilirubin level reaches approximately 2.0 mg/dL (20 mg/100 ml). This condition occurs when the concentration of bilirubin in the blood exceeds its solubility, causing it to diffuse into various tissues, which leads to the characteristic yellow discoloration. With concentrations below this level, bilirubin is usually soluble and thus not visible on the skin or mucous membranes. Conditions like unconjugated hyperbilirubinemia, seen in infants, and liver diseases such as hepatic jaundice or obstructive jaundice, can lead to increased bilirubin levels.