Inquiry on Reprocessing Sample Size Justification

Dear all,

For devices of similar indications as product code KNW (Gastroenterology-urology biopsy instrument), several microbiology testing labs have mentioned that 3 samples is sufficient for sterilization and cleaning efficacy validation for a 510(k) submission based on previous submissions. Does anyone have examples or advice for justification of similar sample sizes for reprocessing efficacy validation?

Additionally, the FDA guidance on reprocessing medical devices states, “The number of simulated use cycles that you use [for validation studies] should be scientifically justified”. For devices of similar indications as product code KNW microbiology labs have mentioned that 6 simulated use cycles per device is commonly used. Does anyone have examples of scientific justification for the number of simulated use cycles?

Any feedback or thoughts on this topic would be greatly appreciated,

Kind regards