Background/Case Studies: To improve outcomes and mitigate risks regulatory and accrediting organizations have requirements for monitoring and controlling temperature (Temp) and relative humidity (RH).Vendors usually provide operating conditions for their equipment, including Temp/RH ranges; however, the conditions may reflect only what was tested and not known points of failure. CTL-Tempe experiences seasonal fluctuations in RH which the building’s HVAC system is not always able to control within the specified ranges of its equipment. Building renovation is not currently an option and portable humidifiers and dehumidifiers could create a source of contamination.A retrospective review of laboratory data was performed to look for negative impacts of Temp and RH excursions on equipment and products and provide data to support expanding the acceptable RH range.
Study
Design/Methods: CTL RH and Temp readings for 2023 were reviewed for excursions outside the initially programmed limits of 20 – 65% RH and 20 – 25oC. Air viable particle counts (AVPC) and laboratory surface cultures (LSC), positive product microbial post-processing cultures, post-thaw viabilities from stability program studies, Colony Forming Unit (CFU) testing, product engraftment, and equipment and supply function problems were also evaluated. Critical equipment manufacturers’ Temp and RH operating ranges were examined to identify equipment with limiting ranges.
Results/Findings: CTL RH readings averaged 15 – 30% January to June, and 70 – 80% July to September. See other representative data from the parameters analyzed in Figure A. Temperature readings were well maintained within the 20 – 25oC range throughout the year with only rare, temporary excursions.Of the 112 pieces of critical equipment, three biological safety cabinets (BSCs) had an operating range of 20 – 60% RH, and one refrigerator’s operating range was < 65% RH. Other equipment’s ranges were within typical CTL RH. Product engraftment data was consistent with historic data back to 2016 and showed no seasonal fluctuations.No trend was noted with the equipment problems during low RH, and such equipment was removed from service until requalified. Conclusions: Evaluation of parameters showed that there was no observable impact of temp or humidity levels on parameters that could affect cellular therapy product quality.With the current HVAC system, CTL frequently experiences RH excursions outside the narrowest vendor-established RH ranges.This data suggests the acceptable CTL RH range can be extended to 15-80%. These parameters will continue to be monitored as part of the Quality Management System and excursions will be evaluated for impact to equipment function and product quality.
