The product KLEIHAUER Erythrosine 0.1 %, aqueous is used in in vitro diagnostics to detect the presence of fetal red blood cells in the maternal blood sample. This is useful to monitor fetomaternal blood transfer during pregnancy and to diagnose rhesus incompatibility in newborns with possible incompatibility. It is also used to stain food samples.

When Kleihauer's erythrosine solution is used in in vitro diagnostics, the erythrosine performs the function of a dye that specifically binds to fetal hemoglobin present in fetal erythrocytes. This binding allows the identification and quantification of fetal erythrocytes in a maternal blood sample. Sodium benzoate acts as a preservative to protect the solution from bacterial growth. The addition of distilled water is used for dilution and provides a suitable consistency for use.