# Implementation of a Blood Cold Chain System Using Blockchain Technology
###### Abstract  
As the population structure changes due to lower fertility rates and rapid aging, the blood supply available for blood transfusion decreases and demand increases. In most countries, blood management information systems, led by national institutions, operate centrally. However, existing centralized blood management systems have limitations in that they lack detailed blood information and, moreover, information is not reflected in real time. To solve this problem, this paper presents an innovative blood cold chain system based on blockchain technology. The proposed system aims to increase information visibility by recording the overall information on the blood supply and providing detailed blood information such as blood consumption and disposal to the distributed ledger. In addition, this paper proposes direct blood transactions between medical institutions in cases of emergency. Currently, blockchain technologies are being actively employed in the supply chain management and medical fields in addition to financial systems. Particularly, private blockchain techniques with limited participants are relatively fast and reliable, making them suitable for B2B (Business-to-Business) transactions. Therefore, the proposed system is based on the architecture of Hyperledger Fabric, a private blockchain technology implemented by the Hyperledger Composer tool. Information in the proposed blood cold chain system cannot be forged or tampered with, and information recorded and shared in real time is kept transparent. In addition, allowing for B2B blood transaction in special circumstances will minimize the blood supply time and enable patients to be transfused quickly. Moreover, the surplus blood of medical institutions will be used to increase the usage rate relative to the supply amount. blood cold chain; blockchain; hyperledger; information visibility +
Footnote †: journal: Medical  
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the Blood Management System (BMS) of the Blood Information Sharing System [1]. Since blood for transfusion is most often consumed or disposed of in medical institutions, information management from a medical institution's point of view is required. Since the blood information of medical institutions is limited to the amounts of blood received and released, determination of the reasons for specific disposals of blood is problematic. According to the World Health Organization (WHO), the blood cold chain represents a system for storing and transporting blood under the appropriate conditions, including temperature, from the blood donor to the final transfusion point [2]. The participants in blood cold chains are blood banks, blood inspection centers, transportation vehicles, and the medical institutions under the blood management headquarters. Due to the uncertainty of blood quality, supply agility among participants is required in order to enable rapid response [3]. Securing information visibility by detecting changes in the supply chain and by sharing information enables a flexible and agile supply chain [4]. Accordingly, once information visibility in the blood cold chain is secured, real-time information sharing and transparent information management among participants can respond to demand efficiently and agilely. Medical institutions secure blood volumes through blood reservations and orders. However, demand uncertainty is high, because the amount of blood required in an emergency that may not occur is constant. The situation is made more difficult because of the inability to use blood after a certain period of time. Research into blood demand response in special situations such as disasters [3; 5; 6] has been ongoing. However, alternatives, such as changing the location of blood banks, increasing the number of blood banks, and setting up specific medical institutions in the supply area for sudden demand, can lead to cost problems and conflicts of institutional interests [7]. This paper presents a new blood cold chain system design methodology based on private blockchain technology.