Endoscope disinfection by ortho-phthalaldehyde in a clinical setting: an evaluation of reprocessing time and costs compared with glutaraldehyde.

Ortho-phthalaldehyde provides high-level disinfection in 12 minutes at room temperature (20 degrees C). To determine whether the endoscopy unit at Massachusetts General Hospital could cost-effectively increase endoscope throughput and decrease delayed procedures while maintaining biocidal efficacy with heavy use, ortho-phthalaldehyde solution (0.55% w/v) was used for high-level disinfection in place of glutaraldehyde in the unit's five automatic endoscope reprocessors. During this 38-day study, 1,839 endoscopes were processed in 1,201 cycles. Each machine ran an average of 80 disinfection cycles in each of three consecutive periods. The shorter disinfection time of ortho-phthalaldehyde (12 minutes) resulted in an average savings of 53 hours in disinfection time per study period for the five processors when compared with glutaraldehyde's 20-minute disinfection time.Ortho-phthalaldehyde costs more per gallon than glutaraldehyde ($31.03 versus $13.20). This higher cost would be offset, however, by additional time savings resulting from the fact that compared with glutaraldehyde, ortho-phthalaldehyde is faster-acting and a mixing and activation step is not required. In addition, testing prior to each cycle verified that despite heavy use, ortho-phthalaldehyde solution remained efficacious, lasting through an average of 80 cycles, whereas glutaraldehyde only lasts for an average of 40 cycles. Test strips showed the concentration of ortho-phthalaldehyde in the reprocessors remained above the minimum effective concentration for the entire 14-day maximal reuse period. Additional microbiological efficacy testing of spent solution diluted to its minimum effective concentration demonstrated the solution remained tuberculocidal in tests with Mycobacterium bovis.