Background and subjects
The 2006 JSDT survey was the first to investigate bacteriological dialysis fluid quality and its management status. Based on the results obtained, the bacteriological standard for dialysis fluid was revised in 2008 , and a chemical contamination standard was added in 2016 .
Compliance with these standards is assessed based on the bacteriological standard for dialysis fluid evaluated by measuring the endotoxin (ET) level and the total viable microbial count (TVC). Both are measured at least once a month. At least one dialysis console at each facility is tested every month, and all consoles are tested at least once a year. The minimum standard required for use in dialysis treatment is designated as “standard dialysis fluid,” meaning that the ET level is under 0.05 EU/mL and TVC under 100 cfu/mL. Ultrapure dialysis fluid (UPD) is defined as dialysis fluid having an ET level under 0.001 EU/mL and TVC under 0.1 cfu/mL. The JSDT standard recommends the use of UPD for all dialysis treatments. Chemical contamination of dialysis fluid was inquired about for the first time in the 2017 survey.
The dialysis fluid standard management status data reported in this chapter were calculated from the data obtained from facilities having at least one dialysis console, and a total of 4388 facilities were included in the 2018 survey.
Dialysis fluid ET testing
The Limulus test is used to perform the dialysis fluid ET level test that is part of the JSDT standard [1, 2]. Since several ET measurement machines are relatively inexpensive and available over-the-counter in Japan, they are widely used by most dialysis facilities. However, it is quite rare in the rest of the world.
Of the 4458 facilities surveyed, 4371 responded to the question concerning the frequency of ET testing, and 3784, which was 86.6% of the total number that responded to this question, complied with the stipulated frequency of “at least once a month” (Fig. 1a, Supplementary Table 1). The annual changes in measurement frequency showed that 33.1% of the facilities performed the dialysis fluid ET test in 2008, the year the standard was implemented, but that the proportion had increased dramatically to 70.6% by 2010, the year in which the dialysis fluid standard additional fee was established, and it has steadily increased since then (Fig. 2a, Supplemental Table 2).
Responses regarding dialysis fluid ET levels were received from 4320 facilities, 3645 (84.4%) of which indicated that they met the UPD standard of under 0.001 EU/mL, and 4199 (97.2%) of them indicated that they met the standard for standard dialysis fluid of 0.05 EU/mL (Fig. 1b, Supplementary Table 1). The annual changes in dialysis fluid ET levels showed that both less than 0.001 EU/mL and 0.05 EU/mL standards are increasing annually (Fig. 2b, Supplementary Table 2). The absence of dialysis fluid ET concentration values in 2008 is attributable to the switch in dialysis fluid ET concentration units from EU/L to EU/mL based on international rules in the survey that year, and the switch resulted in many incorrect entries.
Dialysis fluid TVC testing
A total of 4361 facilities responded to the question regarding the frequency with which dialysis fluid TVC is measured, and 3718 of them, representing 85.3% of all facilities, reported testing at least once a month (Fig. 3a, Supplementary Table 3). The frequency of TVC measurement has been increasing annually, and although it increased markedly in 2010, the same as ET testing did, in all other years, the frequency of TVC measurement has been slightly lower than the frequency of ET testing (Fig. 4a, Supplementary Table 4).
Of the 4248 facilities that responded to the question regarding dialysis fluid TVC, 3361 facilities (79.1% overall) reported meeting the UPD standard of 0.1 cfu/mL, and 4214 facilities (99.2%) reported meeting the standard dialysis fluid standard of 100 cfu/mL (Fig. 3b, Supplementary Table 3). The percentage of facilities meeting the UPD standard and percentage meeting the standard dialysis fluid have been increasing annually (Fig. 4b, Supplementary Table 4).
Achievement quotient of UPD and standard dialysis fluid
Because the JSDT standard stipulates the bacteriological standard for dialysis fluid (both UPD and standard dialysis fluid), the numerical criteria for both dialysis fluid ET concentration and TVC must be met simultaneously [1, 2]. Of the 4244 facilities that responded to the questions about both dialysis fluid ET level and TVC, 3168 facilities (74.6% of those that responded) reported meeting the UPD standard (dialysis fluid ET level under 0.001 EU/mL and live bacteria count under 0.1 cfu/mL), and 4118 facilities (97.0% of those that responded) reported meeting the standard for standard dialysis fluid (dialysis fluid ET level under 0.05 EU/mL and TVC under 100 cfu/mL; Fig. 5, Supplementary Table 5). The achievement quotients for both UPD and standard dialysis fluid have been increasing over time, which suggests that the dialysis fluid purity level is increasing in Japan (Fig. 6, Supplementary Table 6).
Source of dialysis water and chemical contamination preventative measures
A total of 4373 facilities responded to the question in the 2018 survey regarding the source of dialysis water. The most common source was tap water, which was reported by 3700 facilities (84.6%), and it was followed by groundwater (391 facilities, 8.9%), and then by a combination of tap water and groundwater (273 facilities, 6.2%; Fig. 7 Supplementary Table 7). None of these percentages was significantly different from the percentages reported in the 2017 survey: tap water, 85.2%; groundwater, 8.8%; a combination, 5.8% .
A total of 4330 facilities responded to the question regarding the frequency of residual chlorine testing before hemodialysis treatment. “Every day” was the most common response (2587 facilities, 59.7%) and was followed by “once a week” (913 facilities, 21.1%) and then “once a month” (215 facilities, 5.0%; Fig. 8a, Supplementary Table 8). A total of 410 facilities (9.5%) reported that they do not measure residual chlorine. Measurement of residual chlorine has become more common than in the 2017 survey, in which the corresponding data were 55.7%, 21.7%, 5.3%, and 12.0%, respectively. Routine measurement of residual chlorine should be promoted.
A total of 4087 facilities responded to the question regarding their residual chlorine measurement method, with most (1652, 40.4%) reporting that their method measured “free chlorine only,” and they were followed by 1494 facilities (36.6%) that reported using a method that measured “both free chlorine and total chlorine.” A total of 880 facilities (21.5%) reported using a method that measured “total chlorine only” (Fig. 8b, Supplementary Table 8). The proportions of facilities that measured total chlorine had increased since the 2017 survey, when 45.7% measured “free chlorine only,” 32.2% measured “both free chlorine and total chlorine,” and 20.2% measured “total chlorine only.”
A total of 4312 facilities reported familiarity with the JSDT chemical contamination standard , and 85.4% of 4312 facilities reporting either being “very familiar” or “familiar” (Fig. 9a, Supplementary Table 9). A total of 4157 facilities responded to the question regarding the frequency with which they measured chemical contamination as stipulated by the standard; 1769 facilities of 4157 facilities (42.6%) reported “once a year,” while 1124 facilities (27.0%) reported that they do not measure chemical contamination (Fig. 9b, Supplementary Table 9). In the 2017 survey, 37.6% of the facilities measured chemical contamination and 32.8% of them did not. Awareness of chemical contaminants has gradually been promoted by JSDT. Measurements of chemical contamination of dialysis fluid in dialysis facilities have generally been improving, and a survey of chemical contaminations in dialysis fluid should be continued to improve compliance with the JSDT standard.