Abstract:
A process for tracking an object within an inventory control space is provided. The space is illustratively a medical care delivery setting. An active radiofrequency (RFID) tag is encoded with a single-use code and associated with an inventory item. After a trigger event, the RFID tag transmits a modified broadcast. The single-use code that is a new number with at least one sparse digit or a new secondary number with a retained primary digit. An RFID tag configured to retain such a code scheme is provided. A hospital inventory item labeled with such an RFID tag is also provided.

Description:
RELATED APPLICATION 
     This application is a non-provisional application that claims priority of U.S. Provisional Application No. 60/740,962 filed Nov. 30, 2005, the contents of which are hereby incorporated by reference. 
    
    
     FIELD OF THE INVENTION 
     The present invention in general relates to active radio frequency identification (RFID) tagged goods and in particular to a reusable RFID tag automatically updating relation to a particular use event. 
     BACKGROUND OF THE INVENTION 
     A persistent problem with complex organizations is miscommunication as to required tasks to be performed. Such miscommunication is inherent when multiple individuals work on a particular project in shifts or from different locations. Such problems are exemplified in patient care settings associated with hospitals, nursing homes, and clinics where a potentially lethal error results from a patient receiving a medication or treatment intended for a prior bed occupant. Recently, electronic systems have been developed that involve a handshake or electronic identification exchange between electronic recipient and provider components. Such communications include a passive or active radio frequency identification tag communicating with a radio frequency transponder. 
     Unfortunately, a non-disposable RFID tag itself creates a measure of ambiguity as to whether the RFID tag has been coded for a new use or is still projecting an identification signal associated with a prior use. An electronic verification system that incorrectly assigns a pairing between a recipient and donor service pair enhances the likelihood of a process error that the electronic system was intended to preclude. Thus, there exists a need for a reusable radio frequency identification tag that automatically registers a new usage event definition upon registration of identification tag usage. 
     SUMMARY OF THE INVENTION 
     A process for tracking an object within an inventory control space is provided. The space is illustratively a medical care delivery setting. An active radiofrequency (RFID) tag is encoded with a single-use code and associated with an inventory item. After a trigger event, the RFID tag transmits a modified broadcast. The single-use code that is a new number with at least one sparse digit or a new secondary number with a retained primary digit. An RFID tag configured to retain such a code scheme is provided. A hospital inventory item labeled with such an RFID tag is also provided. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWING 
         FIG. 1  is a schematic flowchart of an operating and recoding process for an active radiofrequency identification (RFID) tag according to the present invention; and 
         FIG. 2  is a schematic flowchart of an operating and recoding process for an active radiofrequency identification RFID tag in which the tag trigger event receipt disables the tag to provide a time and location best signal receipt signature of the triggering event. 
     
    
    
     DESCRIPTION OF THE INVENTION 
     The present invention has utility in facilitating correct pairings of donor and recipient component pairs of a process so as to avoid uncertainty as to temporal reset of a reusable RFID labeled component. While the present invention is discussed hereafter in the context of a hospital setting, this is not intended to be a limitation upon the use thereof but rather to afford an intuitive and illustrative usage setting. 
     According to the present invention, a component is associated with an active RFID tag. The term “component” is used herein to define a consumable, a movable piece of equipment, or other item considered as inventory within an institution. In a healthcare setting, exemplary components illustratively include drugs, medical procedure kits, meals, ambulatory pieces of medical equipment, and the like. 
     According to the present invention, upon a predetermined use event, an active RFID tag broadcasts a code associated with the triggered event until disabled. In contrast to the prior art, an inventive RFID tag is rewritten with a new single-use code unmistakable with a previously used code. 
     Referring now to  FIG. 1 , an RFID tag is in a powered-off state  10  until activated to a powered-on state  12  in response to receipt of a high energy transmission broadcast from an authorized controller  14 . Typically, an authorized controller is located at a facility exterior portal such that inventory entering a facility immediately becomes trackable within the facility. When the facility is a hospital setting, a portable piece of equipment or a medicament is recorded as entering the hospital and its whereabouts thereafter discernable. 
     Optionally, in response to an ordered treatment, an association is made between the RFID tag and an active component associated with a patient. As part of the procedure, a handshake is confirmed between the RFID tag and a recipient RFID  18 . In the event the handshake  18  is successful, signaling agreement, usage of the RFID tagged package or device is confirmed electronically. Preferably, authorized use is also signaled in a human cognizable form illustratively including illumination of a light source, an auditory signal or communication of a text message to a personal digital assistant (PDA) or other portable electronic device  20 . In the event that handshake attempt  18  indicates a discrepancy, an alarm is triggered  22  electronically, as well as in a human cognizable form, as detailed above. Regardless of whether a handshake and the resulting authorization  20  or alarm  22  events occur, at some point subsequent to RFID activation at step  12 , a trigger event  24  occurs. A trigger event  24  is appreciated to be variable upon the nature of the product associated with the RFID tag. In a hospital setting a trigger event  24  illustratively includes opening of an instrument or medicament-containing Rim pouch, the RFID tag passing by a particular reading station, or the like. In response to the trigger event  24 , the RFID transmits a unique single-use code in a broadcast mode  26 . A vicinal receiver operates in a coordinated single-use with the RFID. The RFID tag remains in broadcast mode  26  and awaits receipt of a signal  28  indicating that the single-use code provided by the broadcast mode  26  has been received. In the event the RFID fails to receive a read receipt by a receiver, the RFID tag remains in broadcast mode  26 . In the event a receiver transmitted reception signal is received by the RFID tag  28 , the RFID tag determines whether the receipt came from the authorized controller at step  30 . If the read receipt comes from the authorized controller, the RFID broadcast mode is disabled  32 . In the event that the read receipt comes from a data collection receiver  34 , the RFID tag is reprogrammed either to send a disable signal  36  to the RFID tag so as to disable the RFID tag  32 , else the data collection receiver retained the RFID tag in broadcast mode  26 . A data collection receiver being distinguished from the authorized controller in being associated with a location to provide an electronic log of RFID operation; however, it is appreciated that in certain programmed noted, the data collection receiver is a duplicate authorized controller. 
     A disabled RFID tag at step  32  is then recoded for reuse. The present invention operates to recode a non-disposable RFID tag to eliminate the ambiguity associated with a central database lagging in RFID tag update information. The authorized controller reads the expended single-use event code from the RFID tag  38 . The RFID tag receives a command code from the authorized controller placing the RFID tag in a write mode  40 . The single-use event code read at step  38  is stored within the authorized controller or a database in communication therewith. The read single-use code is then used in the creation of a new single-use code. A new single-use code includes a sparse number added to the expended single-use code read by the authorized controller  42 . The sparse number adds or subtracts at least one digit relative to the read single-use code so as to preclude mistake or counterfeiting. In contrast, use of random number generators or other techniques to simply refill each numerical coding bin making up a single-use code retains a finite likelihood of a coding ambiguity, as well as lacking a quickly parsable chronology of RFID tag usage. As an alternative to the addition or subtraction of a sparse number, a primary number associated with the RFID tag is retained while a secondary number is rewritten  42 . A secondary number is illustratively generated by a digital counter integral within the FD tag, the digital counter illustratively measuring rewrite cycles, a local clock signal or the like. It is appreciated that a digital counter functioning as part of a secondary number generated to be rewritten along with a retained primary number operates either alone or in combination with a random number generator. The new single-use code recorded to the authorized controller or the database  44  and is then written to the RFID tag  46 . Depending on the location of intended use of the new single-use coded RFID tag, the tag is either placed in powered-off state  10  or directly into an energized state  12 . 
     Within a hospital setting, writing of a new single-use code to an RFID tag illustratively occurs in a designated area such as a clean room where replenishment or cleaning of equipment occurs. Alternatively, in the case of an equipment lease, removal of the equipment from the leasehold area is the location for RFID tag rewrite. 
     In addition to the operation detailed in  FIG. 1 , it is appreciated that a trigger event  24  has the effect of disabling the RFID tag  32  upon receipt by an authorized controller  30  such that the time and location of the last signal received from the RFID tag is indicative of the triggering event. It is appreciated that in such a mode of operation, steps  30 ,  34  and  36  are not required, yet the system of  FIG. 1  otherwise remains operative, as shown in  FIG. 2  where like numerals correspond to those detailed with respect to  FIG. 1 . 
     The foregoing description is illustrative of particular embodiments of the invention, but is not meant to be a limitation upon the practice thereof. The following claims, including all equivalents thereof, are intended to define the scope of the invention.