Adhered erythrocytes are categorized as reticulocytes or mature erythrocytes based on the fluorescence intensity. Heilmeyer classification groups reticulocytes into 4 groups, group 1 with dense, clumped reticulum, group 2 extended network of loose reticulum, group 3 scattered granules with residual reticulum, and group 4 scattered granules. Mature erythrocytes without nucleic acids are not visible in the fluorescent channel. The same classification and notation are used for distinguishing adhered reticulocytes and mature erythrocytes.