Tracking and tracing of CSSD instruments

How automatic identification technologies like vision-based systems and RFID systems are revolutionizing the tracking and tracing of medical instruments in hospitals.

Automatic Identification Technology in CSSD

Tracking and tracing of instruments and trays in the medical sector
 Documentation, locating and identification of medical instruments are key in hospital hygiene cycle processes. Huge quantities must be decontaminated, the process documented and finally transported to the place of use and back to central sterilization services. Often, this is done manually or only partly automated and therefore it is very time consuming and prone to error. Nowadays, more and more hospitals start to implement automatic identification and data capture (AIDC) technologies to further increase efficiency and to continuously improve hygiene to ultimately prevent infection of patients and personnel.

Automatic identification technologies
Before introducing an automatic identification system, it is important to gain knowledge about the available technologies, as they have individual advantages and disadvantages. With reference to the applications in hospitals, and what is currently widely used in the market, two different AIDC technologies are most suitable: First, vision-based systems and second: radio frequency (RFID) systems. 

Vision based systems use 1D (barcodes) or 2D (data matrix) codes which are applied on the tray or the instrument itself. A code reader camera or a handheld device (like it is known from supermarkets) reads the code and identifies it. A barcode is a sequence of bars and spaces with different widths that contain alphanumeric data. A data matrix code (DMC) adds one more dimension – this means that the information is coded in black and white dots within a square matrix. Usually, they redirect to a central database where all relevant information is stored.

Radio frequency-based systems use electromagnetic or radio waves for communication between a transponder and a read/write head. The transponder (tag) stores all kind of data which is read and written on it by the read/write unit. Finally, a processor unit is used for signal preparation and processing. It typically includes an integrated interface for connecting to the PC system. ​

Comparison of vision and RFID systems
Barcodes and data matrix codes are very cost-efficient solution and are widely used for inventory documentation. Barcodes can only hold a limited amount of information. Often, they are printed on a label which is applied to the tray or trolley. As data matrix codes can be much smaller and hold more information, they are more likely to be used in CSSD. The advantage is that they can be laser-etched on instruments. Beyond that, the error correction when reading a DMC is very high due to information redundancy and error correction algorithm, even 25-30% contamination or damage of the data field can be fully compensated. The downside of DMC and vision-based systems is that there must be a defined distance between the data matrix code and the code reader, and there must be a direct visual contact. Otherwise, the camera cannot read the code.

On the one hand, RFID tags usually do not reach the cost level of data matrix codes. On the other hand, they can hold much more information. On top the information on the transponder can be updated at any time. A further advantage is that the read/write unit reads the tag much faster than a camera would read a data matrix code. On top multiple tags can be read simultaneously which becomes an important advantage if tags are on medical instruments within one tray. Finally, RFID does not need a visual contact. Security becomes more and more important. So, data on the tag can be encrypted, password protected or set to include a “kill” feature to remove data permanently.

Application of RFID and data matrix code systems in hospitals
By securely attaching RFID tags to trolleys, trays, and containers they are then automatically identified and tracked at specific RFID antenna points from operating theatre through to decontamination and sterilization. The instruments inside the trays usually have a laser-etched data matrix code that is read by cameras or handheld readers at specific locations. Due to the flexibility of RFID, there are many case studies and evaluation projects that implement RFID tags directly on instruments. 

Decentralized or central data storage
Another important topic before selecting an identification technology is whether data should be available directly on the instrument or from a central database (cloud). As a data matrix code cannot be updated with information, all data must be stored in a central database. Unlike data matrix codes, a RFID tag can be updated with information from every single step in the hygiene cycle. Even without a server connection, the data can be read with the read/write head. No remote is access needed, so security is increased. 

Value, benefits, and advantages
Using an automatic identification technology leads to multiple advantages that CSSDs can benefit from. They include: Paperless process with reduced search time for critical equipment, significant improvement in overall equipment utilization, unnecessary equipment in inventory eliminated and finally reduced operating costs.

Overview of systems and components that help to reach more automation

Christian Holder
Director - Business Strategy Management, Balluff GmbH, Germany