Incompatibility of dialysis procedure due to hypersensitivity against dialyzer material, currently mainly based on polysulfone and derivatives, cannot be assessed by routine laboratory tests. Although the frequency of such symptoms is suspected to be lower than 2%, it resembles an important clinical problem because dialysis procedures are frequently accompanied by symptoms of non-tolerability with reasons not being entirely clear. To enlighten the role of polysulfone hypersensitivity, we adapted known standardized material immune-toxicological tests (lymphocyte transformation test, basophil degranulation test) to the specific conditions of dialysis and polysulfone material sensitivity. We developed a method of polysulfone micronisation and measured humoral immune response of isolated patient’s lymphocytes when incubated with polysulfone dispersion. Thirty-nine samples from 103 patients with suspected polysulfone hypersensitivity within the dialysis population of a nation-wide dialysis provider (n = 15.761 patients) showed positive results for type 1 (n = 19), type 4 (n = 18) or both type (n = 2) reactions. This is the first methodological report showing plausible in-vitro results of patients’ samples concerning polysulfone intolerance. Further clinical and laboratory research is needed to define true polysulfone hypersensitivity and to enlighten the field of hypothetic subclinical material incompatibility in patients with impaired dialysis tolerability.