In obstructive jaundice, what is the typical ratio of direct to total bilirubin?

In cases of obstructive jaundice, there is an increase in conjugated (direct) bilirubin due to obstruction in the biliary tract, which prevents bile from properly draining into the intestine. As a direct result of this obstruction, you often see a significant elevation in total bilirubin levels, primarily from the increase in direct bilirubin.

The typical ratio of direct to total bilirubin in obstructive jaundice is about 1:2. This means that for every part of direct bilirubin, there are approximately two parts of total bilirubin. This ratio reflects the fact that, while the direct bilirubin is increased due to the obstruction, the total bilirubin also includes an increased level of indirect bilirubin, although to a lesser extent when compared to the direct fraction.

Thus, this ratio helps healthcare professionals differentiate obstructive jaundice from other types such as hepatocellular disease or hemolytic jaundice, where the direct bilirubin levels may differ significantly relative to total bilirubin levels. In obstructive jaundice, the marked increase in direct bilirubin is evident, indicating a pathological process obstructing bile flow.