Steam sterilization and internal count sheets: assessing the potential for cytotoxicity

Count sheets, when placed in contact with surgical instruments during steam sterilization, can transfer ink to the instruments. To explore whether this poses a safety concern, stainless steel instruments were placed on top of completely inked paper and subjected to steam sterilization, extracted, and tested for cytotoxicity. Preprinted labels were examined in a similar fashion. Extracts from stainless steel devices exposed to ink, toner, or labels showed no significant cytotoxic response, although the ink residue on the devices after steam sterilization is difficult to remove and detrimental to the instrument. Placing a barrier between the count sheet and the devices facilitates reuse of the instruments.