cleaning efficacy for the medical devices, and the validated recommendations of both the reusable device manufacturer and the cleaning agent manufacturer, SPDs are responsible for establishing a documented cleaning policy and procedure for the reus- able medical devices they process.

Evaluation techniques There are many techniques used to evalu- ate the results of the cleaning process. The most common, well known, and routinely executed one is visual inspection for vis- ible organic soil (blood, tissue, fat). Often the SPP will use a magnifying glass for external surfaces and a borescope camera for inspecting internal channels of lumened devices. Unfortunately, even if a device looks clean to the inspector, residual or- ganic soil and microbial contamination could be present on an accessible surface that could lead to cross-contamination, infection, granulomas and biofilm fixation. Cleaning verification of external surfaces

and inner channels of instruments with lumens or non-sealed tubular components is not possible by direct visualization alone. Therefore, it’s recommended that SPPs regularly test the cleaning efficacy of auto- mated washers and ultrasonic cleaners, and that they verify the efficacy of the cleaning process immediately after cleaning in such a way as to not damage the device or re- quire re-cleaning. There are several tests used to detect non-visible soil “markers:” • The adenosine triphosphate (ATP) test. ATP is an energy-carrying molecule present in the cells of all living things. However, when the cells die, the concen- tration of ATP decreases over time; this may make detection less accurate.3

• The hemoglobin test. This test was origi- nally designed to detect blood in stool, but has also been developed as a biobur- den detection tool for sterile processing functions.

• Protein testing to detect amino acids (small subunits of a large protein mol- ecule). Forensic scientists use a chemical called ninhydrin, which reacts with amino acids to expose latent fingerprints that are invisible to the naked eye.

Commercial residual organic soil tests ATP testing has been used in the food ser- vice industry for more than 30 years.4


recently, ATP testing is being used in the healthcare industry. ATP tests indirectly

Sponsored by

measure residual organic matter. They re- quire the use of a luminometer to measure relative light units (RLU). A higher RLU indicates more residual ATP, and a lower RLU means there is less ATP on the device. Hemoglobin testing detects blood, but because it was designed to check for blood in stool, it is far too specific and sensitive. Hemoglobin testing measures down to 0.1 microgram and is so sensitive that it does not detect other proteins, such as bone marrow, muscle tissue, placenta, nails, hair and organs. Protein soils are the most common surgi-

cal soils, and any invasive procedure will encounter protein, so it makes sense to test for residual protein on reusable medical devices. Proteins are difficult to remove from reusable medical devices in general, but if they have been allowed to dry they are even harder to dislodge. Since there are many proteins encountered during invasive procedures, a protein test that detects a broad spectrum of protein-based substances is optimal. There are seven recommendations found

in Annex D of ANSI/AAMI ST79 for clean- ing verification tests. The recommenda- tions are that the test be: 1. Rapid 2. Easy to perform 3. Sensitive (i.e., meet realistic benchmarks) 4. Accurate 5. Repeatable 6. Free of interfering substances 7. Robust (i.e., do not require exacting con- ditions or time constraints that cannot be achieved in routine reprocessing areas)

Clinical consequences Healthcare-associated infections (HAIs) and associated outbreaks have been newsworthy events across the country in recent years. Many of those outbreaks have been traced back to insufficiently cleaned devices such as arthroscopic shavers, suction tubes and flexible endo- scopes, all of which are difficult to clean. HAIs are estimated to cost between five and 29 billion dollars per year3

. Surgical

site infections (SSIs) continue to occur at a rate of 1 in 7 cases. Operating rooms today are busy, fast-

paced environments in which one surgical procedure may use multiple instrument sets. A single instrument set may have more than 50 components; multiply that by 4-8 sets per case, and cleaning verifica- tion is no longer an option but an integral requirement of the process.

60 March 2018 • HEALTHCARE PURCHASING NEWS • Reusable medical device designs are far

more complex than in previous years, and with that complexity comes new cleaning challenges. There are numerous cracks, crevices, lumens, channels and a host of other places that provide hiding places for bioburden if they aren’t properly cleaned. Residual soil can contribute to SSIs and other complications. For example, residual protein may trigger an allergic reaction in some patients. Having the full assurance that your cleaning methods are effective is imperative. A quality control measure such as residual soil detection testing is a wise addition to your department’s quality management program. As reusable medical devices become

more complex, methods and inspections post-decontamination also become more challenging. The ANSI/AAMI ST79:2017 document is an invaluable resource to the SPP. Included with the document are infor- mative annexes. Annex D, User verification of cleaning processes, outlines each step of the cleaning process, which must be based on manufacturers’ written instructions for use (IFU) and followed in their entirety. Manufacturers are responsible for de- veloping cleaning processes that address the types of contamination that will be en- countered during patient use. The human body has roughly 10,000 different proteins found in virtually every area, so protein is a commonly used marker for cleaning efficacy evaluation.

Selecting the appropriate test Number six of the seven recommended features of cleaning verification tests in An- nex D is that the test be free of interfering substances. An example of an interfering substance is sodium dodecyl sulfate (SDS) solution, which can cause inflammation in some patients. The procedure to collect eluting samples from endoscopes, oph- thalmic instruments, and devices used in the middle or inner ear can put a patient at risk of injury if the test kit manufacturer’s written IFUs to re-clean the device (to en- sure removal of the SDS solution) are not followed explicitly. If your test product IFU requires re-cleaning, then it does not meet the first recommendation, which is that the test be rapid. The use of sterile normal saline and delivery of rapid results makes modern protein testing user-friendly. The benefit of a test that uses saline is that it does not require re-cleaning. Protein tests are de- signed to be easy to perform (feature #2).

Self-Study Test Answers: 1. C, 2. A, 3. A, 4. D, 5. A, 6. A, 7. C, 8. C, 9. D, 10. B

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