Introduction: The aim of this retrospective study was to evaluate the preservation of biomarkers immunoreactivity on cytospins protected with polyethylene glycol (PEG).
Methods: In two independent cytopathology laboratories, immunocytochemical reactions were retrospectively evaluated on methanol-fixed and PEG-protected cytospins stored at room temperature (RT) for different time periods and compared with immunocytochemical reactions on corresponding baseline methanol-fixed cytospins. Semi-quantitatively assessed immunoreactivity, using scores from 0 to 3, was considered reduced if two sequential scores were lowered by at least one point.