Bilirubin (CAS: 635-65-4) is an orange-yellow tetrapyrrole compound and the primary end product of heme metabolism. As a core clinical indicator of hepatobiliary function, its serum concentration (normal range: 3.4-20.5 μmol/L) is recognized as a "gold standard" for liver function testing by both the National Academy of Clinical Biochemistry (NACB) and the World Health Organization (WHO). The 2023 edition of the Chinese Pharmacopoeia lists it as an active pharmaceutical ingredient (Standard No.: Y-0035).
Chenlv Herb
