Serum total bile acids tests (TBA) are used primarily for the evaluation and monitoring of intrahepatic cholestasis of pregnancy (ICP), a condition affecting 1-2% of pregnant women in North America.
ICP is associated with an increased risk of perinatal complications including premature birth, intrauterine asphyxia, fetal bradycardia and even stillbirth. Severe ICP is defined when serum TBA is above 40 umol/L, and the likelihood of stillbirth is significantly increased when the serum TBA concentration is >100mmol/L, which makes it a good prognostic marker.
However, in non-pregnant individuals with suspected cholestasis, TBA is not an effective test to assess liver dysfunction compared to traditional liver panel tests (e.g., bilirubin, albumin, ALT, GGT and ALP).
In the context of familial intrahepatic cholestasis, the serum TBA is considered as a tier 2 investigation which is ordered by pediatric gastroenterologists only. The urine bile acids profile is the appropriate test for the investigation of disorders of bile acid synthesis, not serum TBA.
Sources :
Azer, S.A. et al. Use of bile acids as potential markers of liver dysfunction in humans: A systematic review. Medicine (Baltimore). 2021 Oct 15;100(41):e27464. PMID: 34731122.
Fawaz R et al. Guideline for the Evaluation of Cholestatic Jaundice in Infants: Joint Recommendations of the North American Society for Pediatric Gastroenterology, Hepatology, and Nutrition and the European Society for Pediatric Gastroenterology, Hepatology, and Nutrition. J Pediatr Gastroenterol Nutr. 2017 Jan;64(1):154-168. PMID: 27429428.
Piechota, J. et al. Intrahepatic cholestasis in pregnancy: Review of the literature. J Clin Med. 2020 May 6;9(5):1361. PMID: 32384779.
Ovadia, C. et al. Association of adverse perinatal outcomes of intrahepatic cholestasis of pregnancy with biochemical markers: results of aggregate and individual patient data meta-analyses. Lancet. 2019 Mar 2;393(10174):899-909. PMID: 30773280.