ASTM D7225-06

Significance—Dried blood represents a significant challenge to cleaning surgical instruments. The water-soluble components of blood are easily rendered insoluble when exposed to heat, chemical solutions, or time at room temperature. The water insoluble component of blood is fibrin built up during coagulation. These proteins bind quite readily to the surfaces of surgical instruments making them difficult to remove even with the aid of chemical cleaning agents. Instruments contaminated with blood residue after reprocessing represent a significant threat for infection to healthcare workers and patients. Healthcare facilities typically employ the use of automated instrument washers. These devices combine mechanical action along with chemical cleaning agents in a staged cleaning cycle designed to thoroughly clean surgical instruments. To function properly, these machines must be performing at targeted mechanical efficiency and deliver the correct chemical cleaning agents at the correct temperature, at the correct dosage for the correct period of time.

Use—The regular, periodic use of the blood soil test is a systemic challenge to the functioning of an automated washer. To properly challenge the cleaning device, the test must be analogous to both the dried blood soil and to the physical barriers presented by surgical instruments. These physical barriers include the box lock, or pivot joint of a hinged instrument, the serrated tips, and crevices of surgical instruments. On the test coupon, the components of blood mimic the state of dried blood on instruments. By mounting the soiled coupon in a plastic holder the physical barriers represented by cracks and crevices of instruments (for example, box locks) are mimicked. Users are provided with an interpretation guide that aids them in interpreting results that are less than optimal. For instance, failure to remove the fibrin layer of blood soil (which is water insoluble) indicates a problem with the chemical cleaning agent(s). Failure to evenly remove a hemoglobin soil indicates a mechanical failure. Failure to remove any soil indicates either a catastrophic mechanical failure, or inappropriate settings for the initial rinse stage.

1.1 This guide is based on a standardized test soil correlating to coagulated blood suitable for screening tests and the evaluation of the cleaning efficiency of washer-disinfectors used for reprocessing of surgical instruments. This guide strictly deals with cleaning and does not describe any methods that are related to disinfection. See the Referenced Documents in Section 2 for additional information.

1.2 The values given in SI units are to be considered the standard.

1.3 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and to determine the applicability of regulatory limitations prior to use.