The task is understood to involve the evaluation and measurement of its promotional activity as the service's use of media and PR becomes more complex.
The move will not affect the NBS's relationship with ZenithOptimedia, which handles its main communications planning activity.
The NBS is thought to be keen to evaluate the impact of its celebrity-driven campaigns, featuring people such as Sir Richard Branson and Gary Lineker talking about how blood donors have helped their families. The ads were created by Delaney Lund Knox Warren & Partners.
In addition to TV and radio, the NBS has developed online campaigns, through Dare, to encourage people to register online as blood donors.
Recent activity has focused on targeting the 17- to 34-year-old age group in a bid to encourage younger people to donate blood.