Serum 7α-hydroxy-4-cholesten-3-one concentrations reflect the activity of the bile acid synthetic pathway. Serum 7α-hydroxy-4-cholesten-3-one values vary during the day as bile acid synthetic rates have a diurnal rhythm.[2]
Elevated values are found in patients with bile acid malabsorption and may be useful in the diagnosis of this condition as high values are associated with low SeHCAT retention.[3] The increase in serum 7α-hydroxy-4-cholesten-3-one concentrations reflects the loss of bile acids secondary to bile acid malabsorption or the increased synthesis found in primary bile acid diarrhea associated with impaired negative feedback of CYP7A1 by FGF19.[4]
^Brydon, WG; Nyhlin, H; Eastwood, MA; Merrick, MV (1996). "Serum 7 alpha-hydroxy-4-cholesten-3-one and selenohomocholyltaurine (SeHCAT) whole body retention in the assessment of bile acid induced diarrhoea". European Journal of Gastroenterology & Hepatology. 8 (2): 117–23. doi:10.1097/00042737-199602000-00005. PMID8723414. S2CID23867181.