↵a The manufacturing conditions in this example relate to ranges that may be near the edge of failure. During manufacturing, the operating ranges may be more narrowly defined.

↵b The thermometer in this example has a variation of 0.5 °C, therefore, the worst-case condition is performed at 17.5 °C so the upper limit of the thermometer is equal to the manufacturing lower limit of 18 °C. The variation in the thermometer's measurement should be considered when designing the virus inactivation study.

↵c In this example, the pH probe has a variation of ±0.05 pH unit. Therefore, when set at 3.85, the lower limit is 3.8, which is equal to the manufacturing upper limit. The variation in pH probe measurement should be considered when designing the virus inactivation study.

↵d Protein concentration in this range has minimal impact on low-pH inactivation. Therefore, in this example the mid-point is selected.