AB-positive
AB-positive was a Human blood type. 

This blood type was one of the two (the other being B-negative) remaining blood types  was required to get for Damron, in order for the Xindi-Reptilian to synthesize a virus for their bio-weapon, which required samples of all eight types of Human blood to be properly calibrated. Once Loomis provided Damron with a patient having this blood type, he would have been paid double the bounty they originally offered him. ()

Physiology