NPEx functions like a telephone exchange where hospital and laboratory systems are connected to one secure NHS datacentre. Pathology test requests and results flow in and out of the central hub to other connected services through a direct interface.

The process itself is paperless, using a messaging engine which translates local data sets and codes from senders to a standard messaging format, mapped against SNOMED-CT coding standards, within the central hub. These messages are then translated once more into the local format of the receiver meaning that users can send and receive requests and results regardless of their Laboratory Information Management System (LIMS). NPEx was originally designed in partnership with the NHS but it is compatible with labs and hospitals run by both the NHS and within the private sector and is also available to be used on an international scale.

A typical NPEx deployment will follow the stages listed below: