Final answer:
Bilirubin analysis is based on its reaction with diazotized sulfanilic acid. Direct and indirect Van Den Bergh tests differentiate between conjugated and unconjugated bilirubin, indicative of different types of jaundice.
Step-by-step explanation:
The analysis of bilirubin is based on the reaction of bilirubin with diazotized sulfanilic acid. The test involves using a Diazo reagent, which is a combination of sodium nitrite and sulfanilic acid in the presence of HCl as a catalyst. In this reaction:
- Direct Van Den Bergh test: Conjugated bilirubin reacts with Diazo reagent to produce a purple-red color within one minute, even without the presence of alcohol. This is an indication of direct bilirubin and is typically observed in obstructive jaundice.
- Indirect Van Den Bergh test: Unconjugated bilirubin does not give a color with the Diazo reagent unless alcohol is added. Upon the addition of alcohol, it produces a purple-red color, indicating indirect bilirubin, which is seen in conditions such as hemolytic and infective jaundice.
Bilirubin itself is a bile pigment, a waste product produced when the spleen removes old or damaged red blood cells. It is further processed in the liver and eventually excreted in the bile, contributing to stool coloration.