**6. How much endotoxin could a patient tolerate without developing a pyrogenic reaction?**

Various endotoxin dose limits have been developed to prevent pyrogenic reactions during and after medical treatments. The European Pharmacopeia [14] defines a limit of 5 EU/kg body weight per hour for intravenously administered drugs, which is also referenced in ISO 23500-1 [15] as the minimum dose that produces fever and is therefore applied in this work to develop a requirement for the endotoxin retention properties of the dialyzer membrane as the last line of protection against endotoxins. During a 1-hour dialysis session, the upper limit of the endotoxin dose for a patient of 50 kg body weight would be 5 EU/kg/h × 50 kg × 1 h = 250 EU. The body weight was taken from ICH Q3(R8) Guideline [16], which defines 50 kg as "relatively low body weight," to allow some extra safety margin.
