Which bilirubin fraction is raised
Urine colour
Stool colour
The chemistry that decides it
Unconjugated (indirect) bilirubin is
fat-soluble and travels bound to albumin, so the kidney cannot filter it and it never darkens urine. The hepatocyte conjugates it with glucuronic acid, making it
water-soluble (direct). Only conjugated bilirubin spills into urine — and only conjugated bilirubin reaching the bowel makes stool brown.
Where jaundice is visible
Jaundice becomes visible at a total bilirubin of roughly
2 to 3 mg/dL. In darker-skinned patients look at the
sclerae, the hard palate and the palms in natural light, not at general skin tone.