Advanced Instrument Processing Solutions

Education: Ask the Expert

The field of medical instrument sterilization is constantly evolving. We encourage all members of the sterile processing community to post their questions. Potomac Labs is committed to education, and we believe knowledge sharing within the sterile processing community-at-large will improve the safety of patients everywhere.

Welcome to our Educational blog

The Potomac Labs team is pleased to present commonly asked questions encountered in sterile processing.

Charles Ciullo, our Director of Sterile Processing, is here to answer your questions.

Feel free to send us your questions–here’s how:

  • Click the “ASK A QUESTION” button (right side of this screen)
  • Include your name
  • Institution
  • City & State
  • Contact email (we won’t post your contact info–it’s just to alert you when an answer has posted)
  • Click “SEND”


Looking forward to receiving your questions.

What is the difference between Neutral pH Enzymatic Detergents and Alkaline Detergents ?

For years alkaline detergents have been used in the cleaning of organic soils from multiple surfaces and substances. They are used in the food industry for flatware, dishes and pots and pans, for the cleaning of laundry both in the home and large scale commercial laundries, in labs for the cleaning of glassware, in life sciences, for cage cleaning and are a favorite in Europe for surgical instrument cleaning.

Alkaline detergents can vary in pH from mildly alkaline (pH 9.5-10) to highly alkaline (pH12-13). Alkaline detergents work by chemically changing organic soil. Alkali’s hydrolyzing peptide bonds, breaking down large insoluble proteins into smaller more easily soluble polypetides. Alkali also works on fats by the process of saponification, which changes fats into soap and glycerin. Alkaline detergents are best suited for mechanical washers because these washers lack the friction that manual cleaning provides through brushing or the cavitation provided from ultrasonic cleaners. Alkaline detergents are usually less expensive than enzymatic detergents but require a higher wash temperature of around 175°F to work properly.

 So why are we in the US so hesitant to use alkaline detergents to clean surgical instruments? First off is that they are corrosive if not dosed properly. Highly alkaline detergents are caustic and not suitable for all materials, a detergent with the pH of 12 should never be used on anodized aluminum (e.g. rigid containers) because it will begin to break down the anodized coating of the aluminum well within 10 washes. Also unless formulated with the right buffers (e.g. deconex Alka One-x ), high alkaline detergents need to be followed with a correctly dosed acid rinse to neutralize any residuals left on the instruments. If they are not buffered or neutralized properly they will begin to remove the passivation layer from stainless steel and corrode the instruments.

On the other hand we have “neutral” pH detergents and “neutral” pH enzymatic detergents. Both forms of neutral pH detergents have a pH range from 7-8.5. Plain Neutral pH detergents are usually considered to be “gentle detergents”. Those intended for use with surgical instruments will normally contain surfactants, chelating agents and if properly formulated anti-corrosive agents. They contain nothing that chemically changes organic soil, but instead depend on their surfactants to lift and remove organic soil from surfaces. There are a few neutral pH detergents that are formulated not only to clean organic soil, but are also capable of removing the residues of High Level Disinfectant from scopes before switching disinfecting processes from aldehydes to amines or visa-versa (e.g. deconex 36 Intensive-x ).

Neutral pH enzymatic detergents “pack the kick” for chemically changing organic soil by the addition of the enzymes. Enzymes are Bio-Catalytic protein’s, they break large organic molecules into their smaller building blocks.  Unlike alkaline’s which target multiple organic substances at once enzymes are specific to the soil they are breaking down. Protease enzymes break down protein, lipase enzymes break down fats, amylase breaks down carbohydrates. The enzymes in neutral pH enzymatic detergents are produce by bacteria.  Subtilisin a protease enzyme was originally obtained from the growing of the bacteria Bacillus subtilis. Presently numerous bacteria and fungi can be engineered to produce specific enzymes, so enzyme manufacturers are not dependent on just one type of bacteria ( e.g Bacillus subtilis) to produce the enzymes they need. Neutral pH enzymatic detergents require a temperature of between 90°F-140°F to do their work. Low temperatures will make the enzymes sluggish and they will not catalyze their target soil properly and temperatures above their working range will denature them. Also until recently most enzymatic detergents were not as efficacious at removing fibrin from surgical instruments as alkaline detergents. The discovery that cellulase will break down this insoluble protein in dried blood has changed this paradigm. Now multi-enzymatic detergents that contain cellulase (e.g. deconex Power Zyme ) do a comparable job to the cleaning power of alkaline detergents when it comes to fibrin removal.


Lastly it should be mentioned that a combination of multi-enzymatic and mildly alkaline (pH9-10) detergents has shown to harness the ability of both modes of cleaning into a superior cleaning system especially suited for difficult to clean instruments like daVinci endowrist® instruments (e.g. deconex Twin pH10/ Twin Zyme ) These are normally packed in separate containers and dosed into the washer disinfector during the wash phase of cleaning.  In the validation study of the deconex Twin System and the Belimed daVinci load carrier for endowrist instruments not one of the instruments in the study had a proteinaceous soil level “above the alert value of 100μg. In fact if you have a dishwasher at home and use pod packed detergent with separate compartments you are already using a similar system on your dishes. The reason for the separate container/compartments is because if you were to combine the chemistries in one container or “pod” they would “cannibalize” each other, but when combined in “concert” in the washer they support each other to gently remove the toughest of organic soils. The separate packaging of these chemistries has recently been overcome by the scientific staff at Borer Chemie. Their latest  product deconex Prozyme Alka is a multi-enzymatic mildly alkaline detergent all in one container. It has no know material compatibility and is even mild enough for use on anodized aluminum, yet its superior clean power is capable of breaking down the toughest of organic soils like fibrin and biofilms. Like all Borer Chemie products it is extremely environmentally friendly to the point that it contains no EDTA or NTA. These chelating agents are widely used in detergents to “soften water” but pose major environmental threats because they accumulate and remain in water unchanged for long periods of time. 

International Healthcare Central Service/ Sterile Processing Week Oct. 12-19 2014

I want to take this opportunity to wish all my colleagues throughout the World a Happy CSSD/SPD Week!! You are all truly the unsung and forgotten HEROS of Healthcare, without whom a facility cannot function, yet few people know who you are and how important your job is. I know from personal experience that if someone asks me what I do for a living and I tell them I’m a Certified Sterile Processing Technician their eyes glaze over they look around quizzically and then ask “what the heck does that mean?” I think it is high time we make ourselves known. Everybody knows what a Doctors job entails, what a Nurse does and even what X-ray and Respiratory techs do, but how many people know what you do for a living? When I explain to people that a Sterile Processing Tech decontaminates assembles and disinfects, high level disinfects, or sterilizes equipment and instruments according to the modalities needed to make them safe to reuse I am usually told “I thought the nurses and doctors did that” (sigh…yes and pigs can fly). All of us who have ever worked in CSSD/SPD know the answer to that.

Isn’t it time you got the recognition you deserve for the job you do? Be proud of what you do, you are patient safety advocates, let people know that! Tell people what you do and how your adherence to recommended best practice and standards keeps patients safe from HAI’s and SSI’s even though you have no direct patient contact. Celebrate your week with your Team too…Yes You are TEAM…I know the tensions that go on in CSSD/SPD, I have worked all three shifts, unless your department works as a “well oiled machine” one shift helping out the other, you will never garnish the respect your department deserves.

 Above all I urge you all to keep yourselves educated and educate others on what you do and why. Always follow recommended best practices, this is what your facility will be audited on by TJC, AAHC, CMS, etc. If you process items “off label” to get things done quicker for a case, it is not the doctor that will be in question in court if there is litigation due to an SSI, it is you. If someone asks you why things are taking so long, tell them you are following the IFU of the manufacturer on reprocessing. Let those who question you see the IFU of what you are reprocessing, unless they have the capability of changing the laws of physics, you are doing things right. Keep yourself abreast of all the newest technologies in Sterile Processing and what is going on in medicine. We live in an ever changing world. The Sterile Processing Department of today is not what it was 30 years ago, instruments have become exceedingly complex and the pathogens we are fighting have become more drug resistant.  Keep the IFU’s for all the equipment you reprocess current and learn about the pathogens you are fighting (here is a link to the CDC’s 2013 antibiotic resistant threats to get you started, yes it’s pre Ebola and EV-D68 but those both are Viruses which antibiotics have no effect on. )


Above all I want to personally Thank You All for working diligently in the most Important Department in Healthcare!

Our facilities Washer/disinfector cycle is approximately 50 minutes long and many times we run into problems when trays are needed that are still in the washer. Is there any way to shorten the wash time without compromising the cleanliness of the instruments?

Here I would like to first say that if there are trays in the washer that are needed for cases, your facility…

A)    Probably needs to increase the inventory of those trays (how a facility can expect to do 15 carpal tunnel cases etc… in a limited amount of time with only 5 trays is ridiculous. The first 5 patients get properly washed and terminally sterilized trays, the remaining 10 don’t? Where is the continuity of care here?)

B)     If you do have sufficient inventory, yet still seem to have trays that are needed for cases in the washer, then someone needs to speak to the OR scheduling department. Obviously cases are being booked too close together.

C)     If scheduling nor insufficient inventory are the cases then, trays are not being delivered to decontamination from the OR in a timely fashion, so I suggest you speak to the Nursing Director in the OR explain your predicament. Instruments that are allowed to sit with debris on them are harder to clean and more prone to corrosion.

If any of the above factors are the reason trays are still in the washer when they are needed I would also suggest you get your infection control department involved in this problem, since they will be your best advocates here.

When it comes to shortening the time instruments are in the washer/disinfector, the only possible place I can see doing that is in the dry time part of the wash cycle, and doing it there will necessitate you employing some chemistry help before hand. Instrument manufacturers, as well as washer/disinfector and cleaning chemistry manufacturers validate the cleaning parameters stated in their Instructions For Use. When you follow the IFU you are doing so to ensure the efficacy of your cleaning process. If the IFU states that you should run said instruments in the ultrasonic for 20 minutes and you do not do so, you are processing the instruments off label. This holds true for the automated washing of your instruments. If you machine is validated pre-wash time is 4 minutes and the validated wash time is 10 minutes and you remove the pre-wash all together and shorten the wash time by 5 minutes are you following the IFU?

I stated before that you can shorten the wash cycle in the dry time part of the total cycle but you would need the help of chemistry to do that, so let me explain. If you add a rinsing aide ( ) in the final thermal rinse of your wash cycle you can lessen your dry time. Rinse aides are basically made of surfactants and lubricants, the introduction of a rinse aide in the rinse water cause the water to bead off surfaces while mildly lubricating the instruments. This means by the end of the thermal rinse your instruments will not be as wet and you can cut the dry time up to 50%. Having dry instruments is important at the end of a wash cycle to help prevent corrosion of the instruments this not only uses a lot of energy but also is one of the dry time can be one of the longest parts of the wash cycle. The only remedy for that is to make them “less wet” before hand and to do that you need a rinse aide.

We have a new CSSD department and some of our instruments are getting a rainbow colored stain on the gold handles and bluing of the stainless steel. Have you ever had this issue? Or do you know the cause?

In reference to the stains on your instruments I would first suggest you have an analysis done of the water you are using in your department. Rainbow stains (annealing colors) and bluing of instruments is caused by a high silicate level in your water. These silicates deposit on the  instruments and cause the staining. These stains can be exacerbated by the use of a high alkaline detergent. High silicate levels in your water also tend to stain the chamber of your washer-disinfector a gold color, so if this phenomenon is occurring it is further evidence of a silicates. Poorly formulated detergents can be another source of silicates, since certain silicates are used as builders in detergents. It may be fine to use them in laundry detergents, but their use in instrument reprocessing detergents can be detrimental (please see…

Also because water vapor can carry dissolved minerals, poor steam quality can be another source of silicate staining, although in this case the silicate stains will leave more of a “snake skin pattern” on the instruments. If these stains are appearing after the instruments have been autoclaved I would suggest having you steam quality checked.

These stains are not harmful if caught in time and can be removed from your instruments with a surgical stain removing soaking bath. Stains in the chamber of your washer-disinfector can be removed by running a full empty wash cycle with this same surgical stain remover, in accordance with the manufacturer’s Instructions For Use (IFU) on dosing ratios and run time (


We have a lot of problems cleaning the soil off of the Bi-polar and Mono-polar surgical instruments at our facility, do you have any suggestions?

The problem of cleaning  eschar off of electrosurgical instruments has been an issue since these instruments first started being used.  As you know these instruments are used to cauterize tissue to minimize the amount of bleeding at the surgical site. This is done by passing an electrical current through the instrument either through opposing tips with different electrical charges or through a mono-polar tip that passes the current through the patient to a grounding pad. In the case of mono-polar cauterization the tip of the instrument touching the tissue does the brunt of the work, while the weakened electrical charge passes through the patient to the grounding pad. (I hope that everyone is checking the insulation on their electrosurgical laparoscopic instruments after each use, since a break in the insulation can cause a “misfire” during a surgical procedure. Electrical current can pass through breaks in the insulation, and if this break is close to any other organ the current will take the closest route out of the instrument, damaging tissue that was not meant to be cauterized).  When these tips cauterize,  tissue, blood and body fluid are basically cooked onto the instrument. This burned on tissue or Eschar (your new $50.00 word) should be removed AT POINT OF USE. Many surgical “kits” come with a little scouring pad that the surgical tech should use to remove the eschar AT POINT OF USE. Each time the instrument is used the eschar should be removed, but we’ve all seen those bipolar forceps with layer upon layer of burned on blood and tissue come into decontamination.  I have capitalized and underlined “at point of use” twice now for a reason, The Association of Surgical Technicians, AORN, and AAMI all state in their recommended best practices that “The cleaning of instruments should begin during the surgical procedure to prevent drying of blood, soil and debris on the surface and within lumens.”(AST RSOP for the Decontamination of Surgical Instruments, Standard of Practice I). If you are constantly receiving electrical surgical instruments with layers of eschar on them, then someone in the OR is not doing their job correctly. Here I would suggest you get together with your manager arm yourself with photographs  of the instruments as evidence and written recommended best practices, the A.S.T. version is readily available on line and set up a meeting with the Director of the OR.

Now as far as the removal of eschar from electrosurgical instruments, my first recommendation would be the use of a stiff plastic brush, soak your instruments as recommended in their IFU preferably in a high quality multi-enzymatic detergent (see our deconex® Power Zyme Brush them under the soak water surface to remove the eschar. If staining from the burned on tissue is still a problem, and the material you are cleaning is stainless steel, I would suggest you use a surgical stain remover (deconex® 34GR is great for the removal of both organic and inorganic stains on surgical instruments and Washer/Disinfectors again refer to the IFU of the product you are using.

One more suggestion I would like to make is that if you are in a larger institution and have more than one washer, you dedicate one of your washers for instruments that are difficult to clean. Use a two component cleaning chemistry system in your washer (deconex® Twin pH10/Twin Zyme Two component cleaning chemistries like the “Twin system” employee both an enzymatic detergent and a mildly alkaline detergent  that when combined in the washer/disinfector  form an extremely effective cleaning system and have demonstrated efficacy in cleaning  hard to clean instruments like the DaVinci Endowrist instruments.


We’ve been told that the washer-disinfectors in our facility are supplied with treated water, but no one seems to know what kind of treated water it is. We are a small free standing surgical center so we have no maintenance department to ask, how can we figure out what kind of treatment system we have?

 Since any water treatment system requires preventive maintenance, either resin recharging in case of softened water, filter tank changes in the case of deionized water, or filter replacement in the case of reverse osmosis water, I highly suggest you first talk to the center’s director and make sure this is being done. If you have a water treatment system that is not being maintained it can do more harm than good, throwing the minerals it was filtering back into the water it was treating. Once you find out the company doing your PM’s, call them up and ask them what kind of water treatment system it is. You might even want to ask them to give you an analysis of your treated and untreated water the next time they come in. Since your detergent dosing ratios are highly dependent on your water quality it is good to know it (no matter what the company who makes your detergent claims, “effective in all water qualities” does not mean you would you use the same amount in hard water that you would use in deionized water).

 Since it may take a while to get in touch with the company doing the service on your water system I am going to give you so clues to look for to help you determine what type of water treatment system you have.


 If you can find them, check to see what type of piping is supplying water to your W/D, if the piping is copper you are probably only using softened water in your W/D. Deionized and Reverse Osmosis water are highly aggressive and will basically eat right through copper piping. If your water is DI or RO it the pipes it runs through will be PVC

 If you can find the water treatment system in your facility try and compare it to the pictures I have supplied here as examples of each treatment modality.

A water softening system usually consists of two components a tank that does the softening and another that contains brine that is used to “regenerate” the resins in the softening tank. Again since softened water is not aggressive the pipes in and out of it will most likely be copper.

A water deionizing system usually consists of more than two filtering tanks one multimedia filter, and a cation and anion filter to remove the positive and negatively charged minerals in the water, these tanks need to be changed on a regular basis and since the resins they contain cannot be recharged on premises. Because pure water is a “universal solvent” the piping exiting a DI system will PVC and not copper, DI water would basically dissolve the copper piping in time, but does not dissolve PVC.

A Reverse Osmosis (also known as high purity water) system usually consists of a pre filter and then multiple filters filled with a coiled membrane that only pure water under “osmotic” pressure can pass through. Minerals and other substances dissolved in the water cannot pass through the pores in these filters they are washed “downstream” with the waste water. Because a smaller amount of “high purity water” is produced to the amount that becomes waste, RO systems normally have a holding tank to contain the “pure water”. As with Deionized water, Reverse Osmosis water is highly aggressive and the piping it passes through is PVC.

Our ASC is trying to figure out the correct standards for how often to change the water for cleaning instruments before reprocessing?

The water in the manual soak sink and ultrasonic cleaner should be changed when it becomes visibly soiled and at least once each shift. The soak sink and ultrasonic cleaner should be rinsed clean before refilling and at the end of the day or between shifts should be disinfected with a lint free cloth soaked in 70% alcohol.

If you are cleaning intraocular instruments, The American Society of Cataract and Refractive Surgery, The American Society of Ophthalmic Registered Nurses and AAMI ST79, Annex N all recommend that the water be discarded after EACH set cleaned. Also for intraocular instrument after cleaning and a tap water rinse all instruments should be rinsed in sterile, distilled or deionized water. This sterile water rinse should provide flow of water over and through the instruments, should not be done in a basin with agitation and should not be reused.

Always follow the cleaning chemistry manufacturers IFU for dosing/dilution ratios. Have your soak sink marked so that when you fill it to that mark you know the amount of water in the sink (e.g. 5 gallons) and dose your cleaning chemistry appropriately. The AAMI ST79 also recommends that you monitor and document the temperature of your soaking solution to make sure it stays in the correct temperature parameters suggested by the detergent manufacturer.

We have had our wash water tested and the silica level is low, yet we still have a snake skin pattern on our instruments after sterilization. Is the wash water the only source of silicates or can they be coming from somewhere else?

There are other sources of silicate deposits which I neglected to mention in my last post on them

One source is the steam in your autoclave. If water to the boiler is improperly treated, minerals that are dissolved in the water can be carried in the steam and deposit on instruments and the chamber of your autoclave.  Silica is also added to some steam boiler systems to protect the boiler and piping from corrosion, if used in excessive amounts this treatment can be deposited on instruments by the steam containing it.

Another source of silicates is in the detergents you may be using. Sodium Silicate (meta-silicate) is sometimes used in cleaning chemistry as a complexing/chelating, buffering and emulsifying agent. As a complexing agent Sodium Silicate has a great affinity for metals and will bind with dissolved metals in water, thus acting as a water softener and preventing dissolved minerals from depositing on surfaces, it is also a great wetting agent and helps keep the components of detergents in emulsion. Many laundry detergents use Sodium Silicate in their formula for this reason and because it has an affinity for metals, tends not to bind to the fibers of clothing.

Another name for dissolved sodium silicate is Water Glass or Liquid Glass and this brings us to its other use. Sodium silicate can be added to the coolant system of a car to repair gaps in the head gaskets. When sodium silicate in solution reaches a temperature of 100°-105°C (212°-221°F) it adheres to the gaps in the head gasket in the form of glass, thus sealing these gaps. The glass that is formed here can only be re-melted at 810°C (1490°F). In the U.S. governments Car Allowance Rebate System “Cash for Clunkers” program, engines of cars traded in had to be disabled so they could not be reused or resold for parts. This was done by draining the oil from the car, replacing it with 2 liters of sodium silicate solution and then running the engine. When the engine got hot enough the sodium silicate would turn glass like and abraded the engine internals causing it to seize.

Given its affinity for metal and the fact that it turns to glass at the boiling point of water, you would wonder why it would be used in any cleaning chemistry for sterile processing, yet it is, because it is a relatively inexpensive substance. It is more common to find this in cart washer chemistry than those for instruments, but here the sodium silicate takes its toll on the washer more than the carts. After repeated uses the cart washer chamber begins to exhibit a coating that one would assume is calcium, but unlike calcium deposits it is not easily remove, even wire brushes have little effect on it. Also this coating begins to build up freezing the washer arm mechanism and plugging the spray nozzles. With continued use the cart washer will become inoperable.

Sodium Silicate deposits

Sodium Silicate Deposits

Should we be using huck towels for instrument tray liners and wicking in our basin sets or would we be better off using disposable tray lines for this?

I personally would suggest you go with disposable tray liners.  For as long as I can remember most of the institutions I have worked in used green huck towels as tray liners, as corner protection under heavy trays and wicking in basin sets etc.., we did it because it is what we had always done. Now new questions on this practice are arising with good reason. If your institution does not have its own laundry facility you send your laundry out to have it washed, do you know what the laundry facility uses to launder these towels? Is there any residual detergents left in these towels after they are laundered? Residual chemistry in huck towels can deposit on instruments during steam sterilization, many laundry facilities use a high alkaline detergent followed by an acid rinse, residue of the chemistries depositing on instruments can cause corrosion. The washing chemistry is not the only factor here, dye transfer from towels onto instruments also comes into play. I know many of us have seen plastic sterilization cases stained from the dyes in towels, if this dye is transferring onto the plastics cases and staining them, is it transferring onto the instruments too? (my guess here would be yes) Now you have these residual chemistries (detergent and dye) on your instruments and I’ve already stated they can cause corrosion of instruments, but they can also cause allergic reactions in those people sensitive to them, something you don’t want occurring at the surgical site.

Lastly there is the problem of lint. We have all been told that these towels are “lint free” but I assure you if you run a lint brush over them it is not coming off clean. What happens when lint, even the tiniest piece gets into the surgical site, the body reacts to it.  Lint is a foreign body it doesn’t belong where it is so reactions such as granulomas and adhesion formation can occur. Also since a particle of lint is much larger than most bacteria, the body will react to it before it detects the bacterial cells allowing them time to replicate and cause major problems.

Sterile huck towels were originally just used to dry hands post scrub before gloving, we in healthcare are the ones who have repurposed them for a hundred other uses than they were originally designed without a second thought.