What is Sterile Processing? A Guide for SPD Newcomers

By Adam Okada

Unless you have worked inside of a medical facility, it’s very likely that you’ve never heard of the Sterile Processing Department (SPD).  Heck, even some people that DO work inside the medical facility have never heard of us.

But Sterile Processing is vital to the operation and success of perioperative services and any other departments where surgical procedures take place.  There is a reason that SPD is also known as the “Heartbeat of the Hospital”.

Sterile Processing is a department inside the medical facility that is primarily responsible for the reprocessing of reusable medical equipment.  Surgical instruments are used on patients during surgery, pre-cleaned at the point-of-use, and then sent down to Sterile Processing for cleaning & decontamination.

Decontamination Area

The cleaning and decontamination of reusable surgical instrumentation and medical devices is the most important part of the Sterile Processing technician’s job.  Manual cleaning of instruments at the sink is performed under the water line to prevent bioburden aerosols from contaminating the air, as well as the SPD technician.  Chemistries used in decontamination (enzymatics, detergents, etc.) must have instructions for use that are followed at all times to ensure proper chemical soak times and water temperature.  All surfaces must be manually cleaned, and all lumens (hollow areas on devices) are brushed and flushed until no bioburden is left inside.  If an item is not cleaned completely, and any gross soil remains on or inside the item (whether the soil is visible or not visible), then the item cannot be sterilized.  Following Standard Precautions (CDC, 2016) means that every item that arrives into the decontamination area is treated as potentially infectious, so that the SPD technician is protected from any potential infectious risk.  Various machines, such as ultrasonic cleaners, washer/disinfectors, and cart washers, can assist the SPD technician to achieve clean and disinfected instrumentation.

Preparation/Packaging Area

The preparation and packaging (prep/pack) area of SPD should be separated from the decontamination area, either in a separate room (2-3 room design) or by a clearly delineated line (1 room design).  Once items have been cleaned and disinfected, they are ready to be prepared by the SPD technicians.  Sterile Processing is primarily a quality assurance department, which means that every instrument must be inspected for cleanliness, completeness (if there are multiple parts), and proper function.  Inspection of all surgical instrumentation and devices is a vital step in the preparation process, as the quality of the instrumentation could mean the difference between a successful surgery or any potential complications.  Items are assembled into pre-determined trays or packs by the SPD technicians following “count sheets” which show the instrumentation listed for that particular tray, and needed in the correct quantities.  Electronic tracking systems are often used to assist with instrument counts.

Once these trays are inspected and assembled per the count sheet, they are ready to package.  Most trays or packs are packaged utilizing one of two methods of tray packaging.  Rigid containers or disposable wraps.  Single items can also be packaged into individual packages called “peel packs”.  Rigid containers are reusable, made of metal, and often used for large sets of primarily stainless steel instrumentation.  Once the rigid container is closed, a verification lock is placed on the end of the container which will turn color after it has been sterilized, and then remains in place until the lock is broken and the container is opened at the point-of-use (during surgery).  The main advantage of rigid containers is their sturdiness and ability to be handled without compromising sterility.  Disposable wraps are also widely used in Sterile Processing packaging.  These are wraps which are folded to completely cover the tray or pack and then taped over with an external indicator tape to maintain sterility.  At the point-of-use (during surgery) the external tape on the wrap is broken and the wrap is unwrapped so the tray can be used.  Disposable wraps are relatively inexpensive and versatile, but are more vulnerable to damage and holes than a rigid container.  All forms of packaging: rigid containers, disposable wraps, and peel packs, must have an external indicator to verify that they have been exposed to a sterilization process, and some form of locking or sealing to verify that sterility has been maintained so they can be stored for later use.  Once any of these locks or seals is broken, or if there is no visible external indicator that the item has been exposed to a sterilization process, then the item must be considered un-sterile and returned to Sterile Processing for reprocessing.


Once items have been assembled, packaged, and labeled, they are now ready for sterilization.  The main form of sterilization in Sterile Processing is a high-temperature method called steam sterilization.  This takes place inside an autoclave where steam is introduced into the chamber, fills the chamber, and penetrates the packages mentioned in the Prep/Pack section.  Steam sterilization primarily sterilizes items through heat, and killing any microorganisms present on the device.

Heat-sensitive items can also be sterilized utilizing low-temperature methods of sterilization.  There are a number of machines available for low-temperature sterilization.  Hydrogen Peroxide (H2O2), Ethylene Oxide (EtO), and Ozone (O3) are the major options.  These introduce chemicals into the chamber, filling the chamber, and penetrating all packaging.  Ethylene oxide kills microorganisms through an alkylation process which disrupts cellular metabolism and the reproductive process.  Ethylene oxide is an effective and broad sterilant, but leaves behind a toxic residue which must be aerated for a minimum of 8 hours before it will be safe for employees to open the chamber.  Hydrogen Peroxide & Ozone kill by a process called oxidation, essentially eliminating the electrons of the microorganism and rendering them unable to reproduce.  Unlike Ethylene Oxide, there are no toxic residuals after a H2O2 or O3 cycle, only hydrogen and oxygen, which makes the chamber safe to open immediately upon cycle completion.


After sterilization is complete, items are cooled to room temperature and sent to a sterile storage location until they are needed for use on a surgical case.  Sterile Storage is a temperature and humidity regulated area which must have minimal foot traffic in order for items to have the best chance to maintain sterility.  Trays and supplies are often kept in the same sterile storage area so they can be easily assembled onto case carts, which are carts utilized for individual surgical procedures.  Some SPD’s utilize SPD technicians to assemble these carts with sterile instrumentation and supplies.

Other Responsibilities

Depending upon the scale and scope of Sterile Processing services, some SPD’s may be responsible for distribution of patient supplies to the hospital, which is also known as Materiels Management.  Some departments clean and distribute patient equipment and some are responsible for the high-level disinfection of flexible endoscopes.  The scope of services can be different based on the individual needs and layouts of specific facilities.

In Conclusion

Due to technological innovations made over the last 30 years, Sterile Processing has become far more challenging due to the complexity of devices and rigid requirements to adhere to strict instructions for use on each item.  SPD technicians must have the ability to focus and remember tens of thousands of instruments, cleaning and sterilization instructions for all those items, and the various disassembly and inspection points.  They must also have the physical ability to routinely lift 25lb trays throughout their 8-hour shift, and maneuver 500lb carts in and out of sterilizers, as well as in and out of hospital hallways.  In addition to the physical and mental drain, the emotional toll taken on by being responsible for the safety and well-being of patients at their most vulnerable is perhaps the most challenging aspect of the position.

Due to this mental, physical, and emotional drain, Sterile Processing can be too much for some people to handle.  I’ve seen technicians walk out after just one day working in the chaos.  But if you are the type of person who enjoys a challenging position with ever-changing priorities, and especially if you like your work day to fly by quickly, there is no more rewarding way to help save patients’ lives than by working in the Sterile Processing Department.


CDC Website (2016) – https://www.cdc.gov/infectioncontrol/basics/standard-precautions.html