To get blood out of machine-washable garments,you need to soak the stain in cold water - preferably as early as possible - use ice, even. Use a fabric stain treater with enzymes designed to handle blood. Or you can use a Fels-Naptha bar. Treat both sides of the garment. Put in a cold water wash and rinse with no rinse additive.
Depending upon how old the stain is, you will need to do this several times.
DO NOT PUT THE GARMENT IN A HEAT DRYER until you get the stain out.