QUANTITATIVE STUDIES OF DIRECT-REACTING SERUM BILIRUBIN

In the presence of hyperbilirubinemia little or no clinical significance is usually attached at the present time to the nature of the qualitative van den Bergh reaction, except in the diagnosis of hemolytic forms of jaundice. Its specificity even in this connection is rendered questionable by the recent reports by Dameshek and Singer¹ of instances of nonhemolytic familial jaundice (serum bilirubin values up to 13.1 mg. per hundred cubic centimeters) and by Malloy and Lowenstein² of apparently nonhemolytic hereditary jaundice in rats, only the indirect van den Bergh reaction having been obtained by these authors. Although the factors which determine the difference between the direct and the indirect reaction are not definitely known, it seems safe to assume for clinical purposes that bilirubin in the serum which does not give the direct reaction has not passed through the hepatic cells and that which does give this reaction has