OG-EA31 Pap reagent is alcoholic polychromatic solution. The first step in using the Papanicolaou staining method implies nuclear staining with a hematoxylin solution, and next two steps consist of counterstaining using the monochromatic OG-6 reagent and one of the polychromatic EA reagent formulations. OG-EA31 Pap reagent does not require three, but two steps because it contains OG-6 and EA31 reagents. The Orange G molecule stains the cytoplasm, and in later stages of the procedure it remains only in the mature, keratinized cells. Polychromatic EA31 solution stains non-stained parts of cell, such as squamous cells, nucleoli, ciliary and erythrocytes. Test samples can be gynecological and non-gynecological, such as sputum, urine, and cytological puncture samples. In order to obtain optimal staining results, OG-EA31 Pap reagent has properties completely in compliance with other BioGnost’s reagents for cytological smearing acc. to Papanicolaou – Hematoxylin HP, Pap 1A reagent and Hematoxylin HP, Pap 1B reagent.