text: Originally, the Van den Bergh reaction was used for a qualitative estimate of bilirubin.
  This test is performed routinely in most medical laboratories and can be measured by a variety of methods.
  Total bilirubin is now often measured by the 2,5-dichlorophenyldiazonium (DPD) method, and direct bilirubin is often measured by the method of Jendrassik and Grof.