Sepsis is defined as life-threatening organ dysfunction caused by a dysregulated host response to infection [1]. Sepsis is characterized by high morbidity, high mortality, and a high proportion of medical intervention ^[2][3][2,3]. According to the statistics, the incidence of sepsis has also significantly increased in recent years, with about 300 per 100,000 people diagnosed with sepsis, while 6% of hospitalized patients are diagnosed with sepsis ^[4][5][4,5]. Nearly $24 billion USD was spent on sepsis treatment in 2013, accounting for 13% of U.S. health spending ^[6][7][6,7]. Sepsis has become a major challenge in the field of emergency and critical medical care worldwide [8].

The standard nomenclature of sepsis began In 1991 [9]. The term sepsis is a broad term, and there is currently no single clinical standard or imaging or laboratory indicators that can be used to uniquely identify septic patients [10]. Therefore, the definition of sepsis continues to evolve and iterate. According to the third edition of the 2016 definition of sepsis, sepsis is defined as life-threatening organ dysfunction caused by a dysregulated host response to infection [1]. Infection is especially emphasized as the starting point of sepsis, rather than a single pathogen invading the body, and organ failure is regarded as an important sign for the diagnosis of sepsis. This is similar to the definition of severe sepsis in sepsis 1.0/2.0, and the definition of severe sepsis has been removed from sepsis 3.0 ^[9][11][9,11]. The diagnosis scale of sepsis changed from SIRS score to ∆SOFA ≥ 2 (Figure 1). It should be noted that, in the diagnosis of sepsis, although the SIRS score has been replaced by the SOFA score, it still has widespread clinical uses, assisting in determining the degree of infection in patients and predicting the onset of sepsis ^[12][13][12,13]. With the introduction of the third version of the definition of sepsis, people’s understanding of sepsis has become clearer. At the same time, the diagnosis of organ dysfunction is added to the definition of sepsis, indicating that the pathological process of sepsis and the related verification response are more complex [14]. The SOFA score citation plays a very important role in the diagnosis of sepsis. Experts believe that sepsis requires a higher level of detection and intervention, and the inclusion of the SOFA score is more convenient for the clinical diagnosis of sepsis while unifying the conceptual differences in the incidence of sepsis, which is conducive to the follow-up development and promotion of sepsis-related research [15].

With the popularization of SOFA score, people have gradually found that the SOFA score has some problems in the diagnosis of sepsis, such as delays in diagnosis, lack of sensitivity, and a complex evaluation ^[16][17][18][16,17,18]. In view of the above problems, different studies have been carried out regarding the application of the SOFA score to diagnose sepsis. On the one hand, the concept of sepsis is extended, in which many emergency critical field experts, led by Dr. Wang, put forward the concept of preventing and blocking sepsis [19], while some scholars believe that patients who survive sepsis have serious cognitive, mental, and physical disorders, and they put forward the concept of post-sepsis syndrome [20]. Countries have also tried different ways of modifying and optimizing the SOFA score according to their own national conditions.

In the 1980s, people found that severe host response disorder infections can lead to multiple organ failure (MOF), which greatly increases the mortality of critically ill patients [21]. With increases in the understanding of organ function, and to describe the MOF degree of patients as objectively and quantitatively as possible, the European Association of critical Care Medicine formally formulated the SOFA score in Paris in 1994 [22]. The expert group believes that the original intention of establishing the SOFA score was to evaluate organ function damage through a limited number of simple and objective indicators, all of which should be easy to measure in hospitals at all levels and should not exceed the scope of routine testing in the intensive care unit [22]. It is worth mentioning that the expert group agreed that intestinal tissue is the first organ to suffer from functional damage caused by infection, and because intestinal function is too complex and there are no readily available and reliable specific indicators, intestinal function was not included in the evaluation system of SOFA score. This problem has been left until now [23]. The proposal of SOFA score provides a very reliable clinical guidance method to reasonably quantify the degree of organ dysfunction. On this basis, people gradually improve their awareness of multiple organ dysfunction, which provides a favorable reference scheme for clinical diagnosis and treatment. In the continuous development of modern medicine, the SOFA score has always been a recognized and reliable evaluation system in critical medicine [24]. The third edition of sepsis guidelines in 2016 regards SOFA scores as the main evaluation system for the diagnosis of sepsis. SOFA score is no longer limited to applications to the critical care system, but has become a research hot spot in emergency and critical areas and has received more and more attention [25]. With the expansion of the scope of application of SOFA score, it was also found to have many shortcomings, and many related studies on modified SOFA score have been carried out. Different countries and institutions have put forward many new ideas for the SOFA score, but these ideas have not yet been agreed on and are still at the verification stage. RWesearchers  will describe the current modifications to the SOFA score in detail in the following pages.

RIn the presearchersvious section, we stated that SOFA score has been a routine method to evaluate the prognosis of patients with multiple organ dysfunction since it was proposed in 1996 [22]. However, there have always been voices challenging the SOFA score; for example, in 2010, the American Medical Association considered it impractical to collect four laboratory parameters in the SOFA score in the event of a massive influx of critically ill patients in an influenza pandemic, natural disasters, or some manmade disasters. Therefore, the laboratory parameters in the SOFA score were cut to a certain extent, and the score was named mSOFAa [26]. However, this modification has not been widely promoted. On the one hand, the purpose of this modification is to deal with sudden public health events and quickly judge the severity of the disease. On the other hand, this scoring system will overlook some critically ill patients who cannot be judged by routine vital signs. After the announcement of new sepsis guidelines in 2016, medical staff in various countries not only adapted and accepted the corresponding new definition of sepsis, but also began to modify the SOFA score for the diagnosis of sepsis. The first station for most patients with sepsis is the emergency room, where the flow of people is large, and monitoring measures are limited. To screen and to identify patients in the emergency room more quickly and to provide timely and positive detection and treatment to patients with risk factors, the SOFA score must urgently be modified. In the nearly six years that have passed since sepsis 3.0 was put forward, countries such as the United States, Australia, Republic of Korea, France, and Spain have successively proposed modified versions of the SOFA score according to national conditions ^{[27][28][29][30][31]} (Figure 2) [27,28,29,30,31]. At the same time, different degrees of improvement tests were carried out according to the low sensitivity of the qSOFA score in the rapid diagnosis of disease. This section will summarize and discuss some of the major SOFA score modifications put forward by countries, as well as the results of the evaluation.