Hey everyone, Washer Disinfector
If you’ve ever walked through a hospital’s sterile processing department (SPD), you’ve probably seen those big, shiny washer-disinfectors (WDs) humming along in a back room, churning through trays of surgical instruments like they’re nothing. I’m from a company that supplies these machines to clinics, labs, and healthcare facilities, and let me tell you—one part of the cycle that catches a lot of people off guard? The pre-rinse. A lot of folks think, “Why bother with a pre-rinse if we’re already running a full wash?” But trust me, skip that step, and you’re gonna run into way more headaches than you bargained for. Today, I wanna break down what pre-rinse actually does in a WD cycle, why it’s non-negotiable, and maybe clear up some myths I hear all the time from new clients.
First off, let’s keep it real. I’ve been working in this WD supply game for 8 years now, and I still hear people say, “We’ll just load all the dirty stuff in, blast it with hot water and detergent, and call it a day.” Nah, that’s like trying to wash a pile of dishes that still have half-eaten pasta on ’em without rinsing first—you’re just smearing that gunk around, right? Pre-rinse is the WD’s first line of defense, and it’s not just a little splash of water. Let’s get into the nitty gritty of what it actually is, for anyone who’s not super deep in the healthcare supply world. A pre-rinse is the initial, cold (sometimes room temp, not hot) water cycle that runs right after you close the WD door and hit start. It’s timed to run for like 1 to 5 minutes, depending on how cruddy the load is. Some machines even have adjustable pre-rinse settings, which we always tell clients to take advantage of.
Now, what’s it doing during that time? Let’s start with the big one: preventing “dried-on debris.” When instruments come out of surgery, they’re covered in blood, tissue, mucus, maybe even tiny bits of bone or bandage scraps. If you leave that stuff sitting on metal (or plastic, or silicone) for even 10 minutes, it starts to dry. Once it dries, it’s way harder to get off—you’re basically fighting a chemical bond at that point, not just surface gunk. Pre-rinse blasts that debris off before it can set. We did a test last year with a surgical set that had dried blood on forceps tips. When we skipped pre-rinse, the main wash took twice as long, and we had to add extra enzyme detergent to get all the blood off. When we ran a 3-minute pre-rinse? The main wash got 90% of the job done in half the time, and we used way less detergent. That’s not just a win for efficiency—that’s a win for costs, which is huge for busy SPDs.
Another big role of pre-rinse: protecting the WD itself. Look, these machines are investments—they cost tens of thousands of dollars, and you don’t wanna ruin ’em early. If all that debris from instruments goes straight into the main wash, it’s gonna get sucked into the WD’s pump, right? The pump is what pushes water through the spray arms at high pressure to clean the instruments. If tiny bits of tissue or food (wait, no, medical debris—you get the idea) clog the pump, it can’t create enough pressure, so your wash is ineffective. Or worse, the debris can scratch the inside of the water lines, or build up on the filter. We had a client last year who tried to skip pre-rinse to save 5 minutes per cycle. After a month, their pump seized up—they had to replace it, which cost them $12k, plus they were down a WD for 3 days, which meant their SPD team had to work overtime to catch up on processing. Oops. Pre-rinse catches that debris in the overflow or the pre-rinse filter, so it doesn’t mess up the rest of the machine. That’s a no-brainer, right?
Wait, let’s talk about something that’s super important for patient safety too. I know, a lot of clients fixate on machine upkeep, but pre-rinse ties directly to patient care. If instruments aren’t properly cleaned, you can have leftover microorganisms on them—bacteria, viruses, even prions (those are the tricky ones that cause things like CJD, by the way). A WD’s whole job is to get instruments to a safe, sterile state, but if pre-rinse doesn’t remove the bulk of the debris, the disinfectant in the next cycle can’t do its job. Disinfectants work on clean surfaces, y’know? If there’s a layer of gunk covering the instrument, the chemical can’t reach the germs. So pre-rinse isn’t just about cleaning the machine or saving time—it’s about making sure the instruments going back to the OR are safe for the next patient. That’s the part that really hits home for me, because this isn’t just selling machines—this is helping keep people healthy.
Now, let’s bust a common myth: “Hot pre-rinse is better, right?” Nah, not usually. Hot water (like 120°F and up) can actually cause proteins in blood and tissue to coagulate—turn that liquid gunk into a hard, crusty solid, which is way harder to remove. Cold or room temp pre-rinse keeps those proteins from setting until the main wash and detergent can break ’em down. Some WDs have a “warm pre-rinse” setting for really tough loads, but I always tell clients to stick to cold unless they absolutely need that warm kick. I’ve seen way too many loads where a warm pre-rinse made the debris worse, not better.
Another question I get all the time: “Do all pre-rinses work the same?” Nope, that’s why when we supply WDs, we make sure clients know how to adjust their pre-rinse settings for their specific use case. A small clinic that does minor procedures might only need a 1-minute pre-rinse, but a major hospital with orthopedic surgery (which leaves way more debris) needs a 4 or 5-minute pre-rinse. Also, the spray pattern matters—our WDs use dual-nozzle pre-rinse arms that blast water at two different angles, so every inch of the instruments gets hit, not just the top ones. Cheaper WDs might have single-nozzle arms, so they miss spots, but even if you have a cheaper machine, cranking the pre-rinse time a little can make up for that.
Wait, let’s get into how pre-rinse interacts with the rest of the cycle, because it’s not a standalone step. Pre-rinse is just the first phase, then you have the main wash with detergent, the rinse to get rid of detergent, the disinfection phase (usually hot water, like 170°F for 10 minutes), and then a final dry. If pre-rinse does its job, the main wash can use less detergent, because there’s less debris to break down. That saves money on supplies, which is a big deal for any facility. We have a client that processes 200 instrument sets a day—they told us after adjusting their pre-rinse settings, they cut their detergent use by 25% in 6 months. That’s a huge cost savings, and it’s all because of a step they were skipping or skimping on before.
I also wanna mention what happens if you do skip pre-rinse regularly. We’ve seen clients who did this for months, and their load quality was all over the place. Some instruments would come out clean, some would have blood stains, some would even have debris stuck in the hinges of forceps. When we talked to them about pre-rinse, they were like, “But we don’t have time!” But here’s the thing: skipping pre-rinse makes the whole cycle longer. If your main wash takes 10 minutes instead of 5, because you have to scrub the debris off, you’re actually wasting more time total. Pre-rinse takes 3 minutes, main wash takes 5—total 8, vs. main wash taking 10, no pre-rinse. So you’re saving time by doing pre-rinse, not wasting it. That’s a common misconception that drives me nuts.
Let me give you a real example from last quarter. We had a new client, a busy outpatient surgery center, that was having issues with instrument reprocessing. Their SPD team was complaining that they were sending out instruments that the OR was sending back because they weren’t clean. They tried everything: more detergent, hotter water, longer main washes. Nothing worked. We went to take a look at their WD cycle, and noticed they had pre-rinse set to 0 minutes—just skipped it entirely. We adjusted it to 3 minutes of cold pre-rinse, and told their team to make sure they didn’t overload the spray arms (another mistake people make). After one week, they reported that 98% of their instruments were coming back from the wash completely clean, and the OR stopped sending instruments back. They saved an average of 2 hours a day on rework, which was huge for a small team. That’s the kind of win we love to see, and it all starts with a pre-rinse that’s not an afterthought.
Now, let’s talk about some best practices, since I’m in the supplier game and want to give people real, actionable tips. First, always match pre-rinse time to your load. If you have a load that’s just minor instruments, 1-2 minutes is enough. If it’s heavy debris from ortho or trauma cases, 4-5 minutes. Second, never use hot pre-rinse unless you have a specific reason—like if you’re processing something with a lot of grease or hard residue that cold water won’t break. Third, make sure your pre-rinse filter is cleaned regularly. Even though pre-rinse catches debris, the filter can get clogged, which reduces water flow. We recommend cleaning it after every 10 loads, or at least once a day. Fourth, don’t overcrowd your WD. If you cram instruments in so tight the spray can’t reach them, pre-rinse won’t help—you’ll still have spots. That’s a load mistake, not a machine mistake, but it ties into how effective pre-rinse is.
Wait, one more thing that’s not talked about enough: water conservation. Pre-rinse uses water, but think about this: if you have to re-wash loads because debris is left on them, that’s double the water, double the energy, double the detergent. Pre-rinse uses a small amount of water upfront to save all those other resources. We have clients that track their water use, and they say that using a proper pre-rinse cuts their total WD water use by 15-20%. That’s not just good for their utility bills—it’s good for the environment, which is a big plus for healthcare facilities that are trying to be more sustainable.
Let’s wrap this up. The pre-rinse in a washer-disinfector cycle isn’t a useless, old step that people added back in the day and forgot about. It’s a critical part that does three main things: 1) removes bulk debris before it dries or coagulates, making the rest of the cycle way more effective; 2) protects your WD from clogs and damage, saving you big money on repairs; 3) ensures instruments are clean enough for proper disinfection, which is essential for patient safety. Yeah, it takes a few minutes, but it saves time, money, and headaches down the line.
If you’re a SPD manager, OR director, or anyone who’s dealing with washer-disinfectors and having issues with load quality, machine upkeep, or costs—let’s chat. We know every facility is different, so we can help you adjust your pre-rinse settings, make sure your WD is optimized, and answer any other questions you have about the cycle. No pressure, just real talk from someone who’s been in this game for years and knows what works.
Drying Cabinet References:
- Association for the Advancement of Medical Instrumentation (AAMI). (2020). Standard for Washer-Disinfectants for Medical Devices (ST 61:2020). AAMI.
- Siegel, J. D., Rhinehart, E., Jackson, M., & Chiarello, L. (2019). Guidelines for Disinfection and Sterilization in Healthcare Facilities, 2019. Centers for Disease Control and Prevention (CDC).
- Boyce, J. M., & Pittet, D. (2002). Guideline for Hand Hygiene in Health-Care Settings. Recommendations of the Healthcare Infection Control Practices Advisory Committee and the HICPAC/SHEA/APIC/IDSA Hand Hygiene Task Force. Infection Control and Hospital Epidemiology, 23(12), S1–S40.
- Rutala, W. A., & Weber, D. J. (2016). Disinfection and Sterilization in Health Care: An Overview. American Journal of Infection Control, 44(10), 1061–1071.
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