Modification of CytoRich Red fixative system for use on bloody Pap and fine-needle aspiration smears.

Recent work has shown CytoRich Red fixative system is effective in lysing red blood cells and reducing background in bloody fluid specimens. The scope of this study was to see whether CytoRich Red can lyse red blood cells in freshly prepared Pap and fine-needle aspiration smears. Paired smears from 20 bloody fine-needle aspirations were prepared. One slide was initially placed in CytoRich Red for up to 30 sec, removed, and then fixed in 95% alcohol. The other slide was placed directly into 95% alcohol. Ten paired Pap smears, one fixed with a commercial fixative and another immersed in a solution of CytoRich Red, were evaluated. All slides were stained with the Papanicolaou stain and analyzed for the amount of red blood cells, background material, and nuclear and cytoplasmic staining. In 100% of all smears utilizing CytoRich Red, red blood cells were significantly reduced without hindering staining. Significant loss of cells from the slides sent in CytoRich Red solution was not observed. CytoRich Red fixative can be effective in reducing red blood cells and background on freshly made smears. In both gynecological and nongynecological cases, diagnostic cells were well preserved and not compromised by blood.