Application of RFID sensor tags in blood quality control management

Feasibility of RFID fusion sensing technology for blood management

The general process of blood management business is: blood donation registration, inspection, blood sample testing, blood collection, blood bank, in-bank management (component processing, etc.), blood delivery, blood bank-Hospital for patient use (or made into other blood products). This process often involves a large amount of data information, including blood donor information, blood type, blood collection time, location, handler, etc. A large amount of information brings certain difficulties to the management of blood. In addition, blood is a very perishable substance. If the environmental conditions are not suitable, the quality of blood will be destroyed. Therefore, the quality of blood will be affected during storage and transportation. Real-time monitoring is also critical. RFID and sensing technology are emerging technologies that can solve the above problems and effectively assist blood management.

RFID technology can provide each bag of blood with its own unique identity and Store corresponding information. This information is interconnected with the backend database. Therefore, whether the blood is at the blood collection point, the transfer point blood bank, or the point of use hospital , can be monitored by the RFID system throughout the process, and the information of blood at each mobilization point can be tracked at any time. In the past, blood was time-consuming and labor-intensive, and manual information verification was required before use. With the use of RFID technology, data can be collected, transmitted, verified and updated in large quantities in real time without precise positioning, speeding up the delivery of blood. Library identification also avoids errors that often occur during manual verification. The non-contact identification characteristics of RFID can also ensure that blood can be identified and detected without being contaminated, reducing the possibility of blood contamination. It is not afraid of dust, stains, low temperatures, etc., and can be used in special conditions where blood is stored. Maintain normal operation under environmental conditions.

Sensing technology is a window for sensing, acquiring and detecting information. It can realize data collection, quantification, processing, fusion and transmission applications. Through the real-time monitoring and collection of the blood environment temperature, sealing status and oscillation degree by the sensor, and then through the system's timely processing and response to the sensed information, the deterioration of the blood can be effectively avoided and the quality of the blood can be guaranteed.

By integrating RFID and sensing technology, and using RFID sensor tags that can not only improve identification efficiency, realize information tracking, and monitor the quality of items in real time, we can truly realize the intelligent informatization of blood management.

Design of RFID sensor tags

RFID sensor tags are mainly composed of micro control units, sensing units, radio frequency units, communication units, positioning units and power supply units, as shown in Figure 1.

1 micro control unit

The micro control unit is composed of an embedded system, including an embedded microprocessor, memory, embedded operating system, etc. It also integrates watchdog, timer/counter, synchronous/asynchronous serial interface, A/D and D/ Various necessary functions and external devices such as A converters and I/O. The main functions implemented by this unit include: responsible for task allocation and scheduling of the entire chip, data integration and transmission, wireless data verification, data analysis, storage and forwarding, routing maintenance of the regional network, and energy consumption management of the chip power supply. wait.

2 Sensing unit

The sensing unit is mainly composed of sensors and A/D converters. A sensor is a device or device that can sense a specified measured value and convert it into a usable output signal according to certain rules. Usually, the sensor is composed of a sensitive element and a conversion element. The sensitive element collects the external information that needs to be sensed and sends it to the conversion element. The latter completes the conversion of the above physical quantities into the original electrical signal that the system can recognize, and passes it through the integration circuit and amplification circuit. The shaping process is finally converted into a digital signal by A/D and sent to the micro control unit for further processing.

Taking into account the requirements for environmental conditions for blood storage and transportation, this sensing unit includes the function of testing multiple physical signals such as temperature, pressure, photosensitivity, and oscillation in the monitoring area.

3 RF unit

The radio frequency unit controls the reception and transmission of radio frequency signals, and selects and uses access methods such as space division multiplexing, time division multiplexing, frequency division multiplexing, and code division multiplexing to achieve simultaneous multi-target identification and system anti-collision mechanisms.

4 communication unit

The communication unit is used for data communication, solving carrier frequency band selection, data transmission rate, signal modulation, encoding method, etc. in wireless communication, and transmitting and receiving data between the chip and the reader through the antenna, and has data fusion, request arbitration and routing. Select functions.

5 positioning unit

The positioning unit realizes the positioning of the chip itself and the positioning of the information transmission direction. Based on wireless transmission protocols, such as IEEE802.15.4 standard and ZigBee protocol. The positioning algorithm can be based on ranging (such as signal strength ranging, time difference ranging, etc.) or not based on ranging (such as centroid method, DV-Hop algorithm, etc.).

6 power supply unit

RFID sensor tags are divided into passive, semi-passive and active. Passive tags do not require a built-in battery in the chip. They work by extracting radio frequency energy emitted by the reader. Both semi-passive and active tags require internal battery power to maintain normal sensing and radio frequency operation. Considering that real-time monitoring of blood products in blood management requires ensuring their continuous and normal energy supply, a power supply unit is added and designed as a semi-passive or active tag [4].

In this part, by reasonably setting the chip's reception, transmission and standby states, the problems of energy consumption and transmission reliability can be solved, and the service life of the chip can be effectively extended.

It mainly introduces from three aspects: blood inbound and outbound management, blood tracking management, and blood quality control management, and points out the effective role of RFID fusion sensing technology in blood management.

1. Blood inbound and outbound management

(1) Blood storage

The staff placed the blood bags at the entrance of the conveyor belt and passed them in sequence. An RFID Reader was installed at the bottom of the conveyor belt. When the RFID sensor tag attached to the blood bag entered the reading and writing range, the information on the tag was read. The middleware filters and transmits it to the backend database. At the same time, the system displays the blood type, type, specifications and other information on the screen at the exit of the conveyor belt. The staff puts the blood into designated storage trays based on the displayed content.

Based on the read blood type, type, specification, quantity, etc., the back-end system identifies the cargo slots in the blood bank and looks for existing empty cargo slots that meet the specifications and quantity. This step is mainly achieved by pasting an RFID tag on each shelf, and writing the blood type, type, specification, quantity and other information it should store through a reader/writer. When a blood bag is placed on this shelf When the blood bag is on the shelf, the staff uses a handheld reader to set and write the RFID tag. When the blood bags on the shelf are shipped out or moved, the staff uses the handheld reader to clear and write the RFID tag. , and the reader/writer installed on the top of the blood bank will read the labels of each shelf under instructions from the system. If it finds a shelf that has been cleared and meets the storage conditions, it will notify the system, and the system will The specific number is displayed on a screen at the storage area, telling staff which type of blood should be placed on which shelves.

After receiving the instructions, the staff will send blood of various specifications to the designated area for refrigeration and storage. At the same time, the reader writes the storage time, storage type, blood sender, blood recipient and other information of each blood bag into the RFID system [5].

(2) Blood out of the bank

The system issues a shipping order, instructing staff to go to the designated area to take out the specified type, specification and quantity of blood. If the amount of blood taken is small, the staff can use a handheld reader to directly read the blood information; if the amount of blood taken is large, the staff can use a conveyor belt to transport the blood out of the library and read its information. The read information is transmitted to the system and checked with the backend database. If it is correct, the shipment is allowed. During the outbound process, the RFID system records the outbound time, blood expiration date and other secondary information.

The order in which blood is shipped out of the library is determined by the system after reading information and analyzing it. Blood of the same specifications is required to follow the first-in-first-out principle to avoid the phenomenon of inventory backlog and expired blood waste. Blood marked as "to be inspected" in the blood bank is prohibited from leaving the bank to ensure the quality of the blood leaving the bank.

2 Blood tracking management

Blood tracking management adopts a cluster-based hierarchical structure. Each cluster head is a distributed information processing center, used to collect data from each cluster member and complete data processing and fusion. Then the data is transmitted to the cluster head of the upper layer and passed in sequence. Finally, all the data is filtered and After integration, it is transmitted to the highest-level cluster head, and the reverse process is the information query process. The data is unfolded layer by layer and tracked in an orderly manner. Here, the highest-level cluster head is equivalent to the national blood information center, while the next-highest cluster head is equivalent to the blood information center of each province, autonomous region, and municipality, and so on, and the lowest-level cluster members are the grassroots blood stations. This hierarchical structure disperses information, avoids centralized storage, solves the problem of excessive information volume, and improves system security. Information exchange and transfer are carried out directly between the child layer and the parent layer, which facilitates query and tracking. The structure is shown in Figure 2.

The blood information storage process is as follows: first, store the RFID identification code of each bag of blood and its corresponding information into the database of the grassroots blood station, then merge the information of the grassroots blood station, and combine the identification code with the effective IP of the grassroots blood station. The address is stored in the local municipal blood information center database, and then the information of the municipal blood information center is integrated, and the identification code and the effective IP address of the municipal blood information center are stored in the local provincial blood information center database. Finally, Then integrate the information of the provincial blood information center, and store the identification code and the effective IP address of the provincial blood information center into the national blood information center database (if necessary, you can also combine the identification code with the national blood information center The effective IP address is stored in the global blood information center database for global blood information interconnection) [6-7].

The tracking process of blood information is: based on the RFID identification code, first search the province information of the bag of blood in the National Blood Information Center database, and then enter the provincial blood information center database based on the found IP address to search for the bag of blood. For city information, enter the city-level blood information center database based on the found IP address to find the blood station to which the bag of blood belongs. Enter the blood station database based on the found IP address. Based on the information, you can know the current status of the bag of blood. The status is whether it is saved in the warehouse, used when it is shipped out of the warehouse, or deteriorated and scrapped. If it has been used, you can further find out all the user's information.

3 Blood quality control management

Blood is very sensitive to temperature changes. If the ambient temperature is not suitable, the substances in the blood will be destroyed, which will affect the quality and shelf life of the blood. Blood should also avoid violent vibrations during storage, transfer and transportation. In addition, the packaging of blood should be sealed. If bacterial contamination occurs due to puncture or other factors, the blood will be discarded.

The RFID sensor tag attached to the blood bag will monitor the environment around the blood bag in real time. At certain intervals, it will measure the surrounding physical signals such as temperature, pressure, photosensitivity, and oscillation, and record the measurement data in the tag chip. . The system will set a standard range inside the tag. Once the current measured data is lower than the lower limit of the range or higher than the upper limit of the range, the tag will actively transmit a radio frequency signal to activate the alarm device to prompt the staff.

If the blood bag is alarmed while it is being stored in the blood bank, then based on the received radio frequency signal, the current location of the alarmed blood bag (storage area, shelf, RFID identification code, etc.) will be displayed on the alarm display to facilitate staff to promptly detect and Processing; If the blood bag is to be alarmed during transportation, the alarm device can be installed on the transportation storage container to alert the staff with a whine or flash. After the staff finds out, they use a handheld reader to receive the radio frequency signal and find the alarm based on the identification code. Blood bag.

Once the blood is suspected to be spoiled or contaminated, the staff will use the reader to set the label to "to be inspected" and will not be allowed to leave the warehouse. Blood that is already at the point of use is not allowed to be used. After testing, it is confirmed that it cannot be used. , high-pressure sterilization and incineration will be performed. At this time, the staff will write the scrap information, scrap reasons, etc. to the system with the RFID identification code of the bag of blood to prepare for subsequent blood tracking.

For returned blood, in addition to further manual testing of blood quality, the data records of RFID sensor tags can also be used to find out the links in the entire process from blood collection to blood supply to withdrawal of blood, and to find out who is responsible. The person or organization needs to analyze the reasons to avoid similar situations from happening next time.

Blood is not only the source of life, but also a channel for the spread of many diseases. Common diseases spread through blood transfusions or blood products include: hepatitis B, hepatitis C, AIDS, syphilis, malaria, sepsis, etc., most of which are difficult to cure. In order to avoid disease transmission or medical accidents caused by irregular blood collection, chaotic management of bagged blood, or improper blood transfusion, it is imperative to strengthen blood management and ensure the safety of blood use. At present, the combination of RFID and sensing technology is not widely used, but it has shown broad application prospects. This article proposes an RFID sensor tag designed by integrating these two technologies, and analyzes the advantages and feasibility of applying it to blood management.

Blood management is a work that does not allow for errors. The application of RFID sensor tags not only makes the entire supply chain management visible, transparent, and free from contamination, but also enables real-time monitoring and interconnection tracking of information and quality, truly making blood The work of management informatization and medical management informatization has been extended to the ends and implemented, so that completely individualized humanistic care can be realized.