Thus, evidence of hemolysis, extravascular collections of blood, sepsis, hypothyroidism are all absent. Without treatment, the jaundice shows a continually rising trend. The hemoglobin levels, reticulocyte counts, bone marrow morphology and red blood cell survival are all normal. Liver function studies are normal and there are no abnormalities of the extrahepatic biliary system. No bilirubin is found in the urine.
Feces are of normal color, despite low levels of fecal urobilinogen.
The bile is colorless or pale yellow and contains little or no bilirubin. Of the small amount of bilirubin present in bile, the majority is unconjugated with small amounts of monoconjugates and traces of diconjugates. I requires an assay of the enzyme UGT in hepatic tissue obtained by biopsy. The activity of this enzyme is undetectable. The viability of the sample should be tested before declaring this result.