Determination of bile acid pool size in man: a simplified method with advantages of increases precision, shortened analysis time, and decreased isotope exposure.

A simplified isotope dilution method for measurement of the bile acid pool size in normal subjects is described and compared with the traditional method of Lindstedt (Acta Physiol. Scand. 40: 1-9, 1957). Advantages of this simplified method include a four- to eightfold reduction of isotope dose, facilitation of analytical procedures, and a reduction in the required number of duodenal intubations. In 15 human subjects who had two separate estimates of pool size by this method, precision averaged 2.6 percent. In 16 comparisons, pool size measured by this method averaged 13.7 percent higher than simultaneous estimates by the Lindstedt method. Factors affecting accuracy (as opposed to precision) in both methods are discussed.