Range of serum bile acid concentrations in neonates, infants, older children, and in adults.

Serum total bile acids (tBA) determination is a non-invasive, simple and very sensitive diagnostic test in evaluation of liver disorders. However, its usefulness is limited by lack of the data on normal value range of serum tBA concentrations in children, especially neonates and infants. The aim of the study was evaluation of serum tBA concentrations according to the age and gender of children, and their comparison with the values found in adults.Serum tBA concentration measurements were performed using enzymatic-colorimetric test Enzabile (Nycomed Pharma, N) in blood samples collected 3 hours after last meal in newborns and infants, and fasting in children over 1 year of age. The studied children were healthy, without any abnormalities on physical examination. In adults, the measurements were performed in fasting patients with inguinal hernia without any other concomitant diseases scheduled for elective surgery. Two hundred seventy eight children (145 females and 133 males) of ages ranging from the 1st day of life to 16 years, and 63 adults (39 males and 24 females) were investigated.Serum tBA concentrations in newborns (mean (SD: 19.6 +/- 5.2 mumol/l) were significantly higher than the values found in adults (5.1 +/- 2.9 mumol/l). Serum tBA concentrations increased gradually after delivery, with peak values occurring at the age of 1 month (22.2 +/- 5.1 mumol/l), which then gradually declined to nearly adult levels. No gender-related differences were observed in serum tBA concentrations in children.It is mandatory to refer to the age of the patient, interpreting values of serum tBA concentration in children.