I've never done it with red blood cells but normally a chromium 51 taggable (51Cr is used in medicine)

1.5 106 cells in culture medium 200µl + 20µl Na2Cr51 (200µCi) incubation 1 h 00

red blood cells use Fe for their heme production, so may be Fe-dextran can help? But never tried it

Thanks, philippe. But I need a specific  fluorescence dye.

Thanks, Steven. What do you mean 'Fe-dextran'? Further more,  dextran is used commonly o decrease vascular thrombosis. Platelet can also bind with dextran. My purpose is to label RBC only but no effect in thrombosis.

To my knowledge the glycophorin A (membrane protein) is specific to human erythrocytes (mice? I don’t know) You can maybe use a fluorescent antibody

Fluorescent labeled dextrans can made be in variable sizes some that pass endothelial bariers, others not. I now it is used to analyze and quantify heme production but have no idea whether you can use it for tracing.

As wel you can use transgenic mice: EpoR-cre mice specifically  expresses cre from CFU-E stage and crossed in with a conditional Rosa26-YFP reporter you label all RBC with YFP. It works good for FACS but for in vivo analysis you probably need a stronger reporter.