Impeccable sample fixation is a prerequisite for a correct cytological diagnosis. Tissue samples must be immersed in an optimally chosen fixative immediately after sampling, while they are still moist. Imminent fixation of the sample prevents drying and cell shape change, in turn enabling clear staining and a correct diagnosis. If the sample was fixated later than it had been recommended, brownish grainy structures will form on cytological samples stained according to Papanicolaou, and that has a negative effect on the further diagnostic procedure. Used for fixating Pap smears.