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A Proactive Approach to Surgical Instrument Stains
By Sara Freiberg

(Features Surgical Instrument Staining Guide)

German-made stainless steel surgical instruments are made from 300 or 400 series steel. During the manufacturing process, instruments go through multiple steps prior to the finished product. Manufacturing begins with forging, a process for shaping the metal parts by applying pressure to the metal in either a hot or cold state, and through hand or hammer forgings. After a crude shape impression is forged, excess material is trimmed to give a more desirable shape to the instrument. Removing excess material allows the manufacturer to create a variety of features on the instrument, such as serrations, ratchets, male and female box cuttings, and various types of grooves, all of which create the instrument’s unique patterns.

A heat treatment is performed to change the instrument’s physical and mechanical properties without changing the original shape and size. Heat treating improves product performance by increasing instrument strength. An important chemical treatment called passivation is initiated to clean the surface of the steel parts, remove any burrs, and increase the instrument’s corrosion resistance. Instruments are set to align with their proper function and are polished and buffed to allow the various appearances on the instrument’s finish, such as mirror, satin, or matte. Finally, a quality check is performed to confirm the desired specifications and, upon final inspection, they are packaged.1

The importance of passivation
Passivation is important in the manufacturing process and for the end user. The manufacturer initiates the passivation process to restore the instrument’s original corrosion-resistant surface by forming an oxidized layer on the instrument. Damage to the passivation layer is the key to understanding how instruments can develop stains. The term “stainless” steel can be misleading because there really is no true stainless type of steel; therefore, if instruments are not properly cared for, the passivation layer can become damaged and instruments can develop stains.

How does the passivation layer become damaged? 
Older instruments are well protected by an effective layer of chromium oxide and strengthened by the repeated exposures of oxidizing conditions during reprocessing, sterilization, and use. Proper cleaning and sterilization protocols allow the layer of chromium oxide to improve over time, decreasing the potential of staining. Stains due to metal deposits or plating stains (mixing dissimilar metals) often occur near the magnetic parts of the instrument. New instruments have not had time to build up their chromium oxide layer and are highly magnetic in the locks, serrations, and ratchet areas. This magnetism gradually wears off during reprocessing, sterilization, and use. All instruments have the potential to become stained; however, we may see that newer instruments tend to stain more easily.

Improper care and handling can drastically reduce the life of any surgical instrument, and staining can damage the instrument if not addressed promptly. Instrument staining often occurs from deviating from the instrument manufacturer’s instructions for use (IFUs). You need to take a closer look at the various products or systems (i.e., water quality, detergent pH, etc.) used in the sterile processing department and operating room environment. It is imperative that both sterile processing and operating room departments work in unison in caring for their valuable surgical instrumentation to ensure they last for many years.

Care begins at point of use
The biggest enemies of stainless steel surgical instruments are blood, debris, and saline. Over time, instruments subjected to these areas will cause a breakdown in the passivation layer. Preventing stains on instruments begins in the operating room environment. Throughout the surgical procedure, instruments should be wiped, rinsed with sterile water (not saline), and any gross soil should be removed prior to handing the instrument back to the surgeon. This routine ensures best practices are followed, and it mirrors the instrument manufacturer’s IFUs for instrument care.

It should be noted that saline is highly corrosive to surgical instruments and should be avoided at all costs. Following the procedure, any instruments that were not used should be restrung on their instrument stringer and placed back into the tray, separated from soiled instruments. Soiled instruments should be kept moist, either placed in a basin of sterile water or a moist towel, or sprayed with an enzymatic agent prior to transportation to the SPD. All instruments should be placed in covered containers and placed back in the case cart. It is imperative that surgical instruments are not left in water for extended periods of time; therefore, immediate transportation to the SPD is extremely important. 

Prevention is better than cure
Following the IFUs for surgical instruments, detergent, ultrasonic cleaner, and sterilizer is critical for the longevity of your surgical instruments. Water and steam quality should be periodically monitored to eliminate any impurities. Steam sterilizers should be checked often and maintained according to the sterilizer IFUs to ensure a well-functioning drying cycle. Instruments should come out completely dry, whether in wraps or in trays. Stains can be removed with either stain removers or buffed out, although true rust will cause permanent damage to surgical instruments if not addressed in a timely manner. It is important to act quickly if staining is a concern. Any potential delays will compound the problem and patient safety may be compromised.

In an effort to reduce the expenses associated with maintaining surgical instruments, many hospitals find that prevention is better than cure. As a result, facilities are following the recommended guidelines, working closely with their repair specialists, and developing department protocols for proper instrument inspection, maintenance, and longevity.

Stains on instruments appear in many colors and, in most cases, the colors can lead you to the origin of the stain.2 A proactive approach to avoiding stains is the best practice and one that should be followed throughout the instrument lifecycle.

Protect your investment. With the proper care and handling, and using a staining guide in your department, your surgical instruments may last for many years to come. Your patients, surgeons, and facilities will thank you.

Click here to access the Surgical Instrument Staining Guide.


  1. https://aboutsurgicalinstruments.wordpress.com/2012/02/06/70/
  2. http://ww.miltex.com/prodInfo/productCare.aspx#2

Staining Guide References






Sara Freiberg, CST, CBSPDT, CER, has more than 15 years experience working as a certified surgical technologist, with five of those years spent traveling to various operating rooms across the U.S. Following Sara’s time in the clinical arena, she worked as a surgical technology didactic and lab instructor at Rasmussen College. Sara holds bachelor degrees in science and business and marketing, which led to her work with various medical device companies as a clinical specialist, product manager, and clinical training manager. She has experience working on quality and regulatory teams, monitoring patient-adverse events, and postmarket surveillance activities.

Sara currently works for Northfield Medical as a clinical education manager where she provides education which is based on current manufacturer and regulatory guidelines regarding various healthcare topics for SPD, OR, and GI staff. Training entails the care and handling of medical devices to ensure patient safety, as well as targeted education addressing departmental cost concerns. Her passion is working with SPD, OR, and GI departments; providing assessments; and sharing best practices with respect to patient and staff safety, surgical instruments, and medical devices. Sara is a voting member of the AAMI ST/WG84, ST91 flexible endoscope committee, and she has developed several CEU presentations approved through CBSPD, CBRN, NCCT, and IAHCSMM. Sara also authors a biweekly healthcare article for Ultra Clean Systems.

Sara is currently studying for the Certification Infection Control (CIC) exam through APIC.

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