New red blood cell lysing fixative for use in fine needle aspiration and fluid cytology

OBJECTIVE: To describe a new red blood cell (RBC) lysing fixative, Devine's lysing solution (DLS), that increases the diagnostic utility of fine needle aspiration (FNA) and fluid cytology. STUDY DESIGN: Twenty bloody FNA cases were fixed with either DLS or 95% ethanol, and the ability to render a diagnosis on these materials was analyzed. DLS was compared to the red cell lysing fixative CytoRich Red (CRR) (TriPath Care Technologies, Burlington, North Carolina, U.S.A.) in its ability to lyse RBCs by mixing human RBCs with the U266 multiple myeloma cell line. DLS was compared to CRR in its ability to suitably preserve materials for Papanicolaou and immunocytochemical analysis. RESULTS: Comparison of DLS with 95% ethanol fixation in 20 bloody FNA cases prepared in duplicate showed that DLS reduced from 17 to 3 the number of cases that had RBCs obscuring > 25% of the diagnostic material. In 3 cases, DLS enabled the rendering of a definitive diagnosis of malignancy, which could not be made on the ethanbl-fixed material. DLS was compared to CRR, and both fixatives were similarly effective at lysing RBCs, preserving the cellular morphology of diagnostic cells in FNA and fluid cytology, and preserving cells for use in immunocytochemistry. CONCLUSION: DLS increases the visualization of diagnostic cellular material when compared to ethanol fixation. DLS is comparable to CRR in RBC lysing ability, diagnostic cell preservation and preservation of materials for immunocytochemistry.