The Kolplast Group presents to the laboratory market the line of Cytological Dyes – Harris Hematoxylin, Orange G and EA-36 – developed to guarantee quality in the staining of slides for cytological examinations. Consistent and of high quality, they provide clear staining, highlighting both cell nuclei and cytoplasm. It also maintains the integrity of the stain, even after prolonged storage.  Papanicolaou staining Staining plays a fundamental role in cytology and histology for the accurate identification of neoplastic, malignant or benign lesions, as well as contributing to the diagnosis of inflammatory and infectious processes in various samples. For this reason, the choice of each dye must be based on the desired end result and is applied differently to each type of material to be evaluated. In cytology, the most common staining method is the Papanicolaou stain, a multichromatic technique that allows for cell differentiation, which is evidenced by the different shades acquired by each cell type. The cell’s dye affinity is related to the acidic or basic components found in the nucleus and cytoplasm. In the development of Kolplast dyes, the focus has remained on the importance of proper staining for cytological studies, which is directly related to the recognition and identification of cells from malignant lesions. This is because nuclear and cytoplasmic changes can be better visualized in well-stained samples. The colors should be vivid, allowing the differentiation of cell types through the coloration of the cytoplasm and thus facilitating the perception of neoplastic alterations, as well as the presence of cytoplasmic keratinization. The nuclei should be well stained, while maintaining the subtlety of nuclear details such as chromatin and nucleoli, important structures that also help in the diagnosis of malignancy. In order to achieve the gold standard of staining and maintain the shade of the stained cells for a prolonged period of time, it is important that the samples are properly fixed immediately after collection to preserve the cellular components. Changing the liquids and cleaning the staining vats frequently also contribute to the quality of the test.