Bisphenol A [BPA, 2,2-bis(4-hydoxyphenyl)propane], an industrial chemical used 
in the production of polycarbonate, epoxide resin, and polyarylate, is 
considered to be an endocrine-disrupting chemical. BPA may be present in some 
hollow-fiber dialyzers used in hemodialysis. In this study, we tested the 
amounts of BPA eluted from various hollow fibers. Furthermore, we measured the 
BPA concentration in the sera of 22 renal disease predialysis patients, as well 
as 15 patients who were receiving hemodialysis, to see if there is BPA 
accumulation in these patients. The elution test of BPA showed that a much 
larger amount of BPA was eluted from polysulfone (PS), and 
polyester-polymeralloy hollow fibers. Among renal disease patients who had not 
undergone hemodialysis, the serum BPA concentration increased as the renal 
function deteriorated, showing a significant negative association. In a 
crossover test between PS and cellulose (Ce) dialyzers, the predialysis serum 
BPA concentration of PS dialyzer users decreased after changing to a Ce 
dialyzer, and the serum BPA increased again after switching back to PS 
dialyzers. In patients who were using PS dialyzers, the BPA level significantly 
increased after a dialysis session. However, in the Ce dialyzer users, the BPA 
level decreased. Since accumulation of BPA could affect the endocrine or 
metabolic system of the human body, it is important to perform further 
investigations on dialysis patients.