Challenging the six-hour recommendation for reprocessing sterilizable medical equipment

At present, reprocessing of sterilizable medical equipment is recommended to be initiated within 6 h after completion of surgery, to ensure that the quality of the instruments does not deteriorate. A literature search showed a lack of evidence for consequences that may occur if medical personnel deviate from the standard 6 h sterilization protocol.

To evaluate the 6 h recommendation for reprocessing sterilizable medical equipment by determining whether residual protein increased proportional to holding time before reprocessing was initiated, and likewise whether an increase in corrosion was present on surgical scissors proportional to holding time.

Residual protein was identified on surgical instruments contaminated with human blood after different holding times and before washes using the o-phthaldialdehyde (OPA) method. Corrosion was identified on surgical scissors contaminated with human blood after different holding times and after reprocessing using light stereomicroscopy and scanning electron microscopy.

Protein residues ranged between 14.0 and 51.9 μg and thus below the accepted threshold of 100 μg per instrument surface. Corrosion corresponding to 0.05% of the surface was identified on 22 of 30 scissors. Pitting corrosion was seen on four of 30 scissors.

No association was identified between residual protein and holding time, nor between incidence of corrosion and holding time. The study thereby challenges the relevance of upholding the recommendation of a maximum wait of 6 h prior to reprocessing. The findings will potentially have an impact on the organization of reprocessing of surgical instruments in Denmark and internationally.