blood test (act of taking a blood sample in order to have it analysed)

blood drive (activity, usually charitable, in which persons are requested to donate blood, either to maintain a general supply or in response to a specific shortage or emergency)

jus sanguinis

bloodbath, bloodshed

plural of bain de sang

blood donation

(transitive, figuratively) to have an innate ability in something, to be naturally gifted for something

(figuratively) to sweat blood (to work extremely hard)

(idiomatic) to keep one's cool; to keep a cool head

to lose one's cool; to lose one's head