This story in RFID Journal describes Philips Medical Systems' RFID solution. Philips teamed up with AeroScout, using their tags and positioning engine software. Here's an overview of the solution:

Built on a suite of software Philips designed to help health-care
institutions manage their staff, patient care, assets and operations,
the system has been integrated with real-time location system (RTLS) hardware and software from San Mateo, Calif.-based RTLS specialist AeroScout.
The RTLS system includes AeroScout T2 active RFID tags; AeroScout
Exciters, which activate the tags to transmit their ID numbers, thus
providing location information whenever tags pass by their locations;
and AeroScout Engine, a software component that calculates tag locations by processing data from Wi-Fi access points and the active
tags. AeroScout's MobileView software associates each tag's ID with the
corresponding device, while also collecting and storing location data.
The MobileView software can also portray location information on a map,
or in a table or report format.

I'll be talking to both Philips and AeroScout at HIMSS about their joint solution. Pictured right is an AeroScout tag.