Earle H. Spaulding

Earle H.Spaulding, Ph.D., Departement of Microbiology, School of Medicine, Temple University Medical Center, Philadelphia, Pa. He defined the classification of instruments within the needed steps for reprocessing and maintainance circle.

The Spaulding Classification classifies all items used during a treatment into three levels to ensure they receive the appropriate reprocessing process. The three levels are ‘critical’, ‘semi-critical’ and ‘non-critical’, depending on the contact of, for example, skin, blood, or mucous membrane.

Please always refer to the relevant manufacturer’s instructions for use as well as your local guidelines based on this classification.

Sinner's Circle

Sinner's Circle was invented in 1959 by Dr Herbert Sinner. He worked for the German company Henkel. He summarized the four factors Chemicals, Mechanical, Time and Temperature into the basic principle of cleaning and that determine the success of a wash.


Validation is a documented procedure for obtaining, recording and interpreting the results required to establish that a process will consistently yield product complying with predetermined specifications. (Source: EN ISO 15883; (ISO/TS 11139)

Corrosion - corroded

Corrosion is defined as the destructive and unintentional degradation of a material caused by its environment. Unfortunately for metals almost all environments can cause corrosion to some degree, since the corroded state is the more stable state (in Chemistry). A common type of corrosion is rust, which is found on iron and steel structures. In this type of corrosion, the iron is reacting with oxygen to form iron oxide compounds.


An abnormal form of a normally harmless protein found in the brain that is responsible for a variety of fatal neurodegenerative diseases of animals, including humans, called transmissible spongiform encephalopathies.


Protein and polysaccharide substances called pyrogens, released either from bacteria or viruses or from destroyed cells of the body, are capable of raising the thermostat and causing a rise in body temperature. Fever is a highly significant indicator of disease.


Sepsis should be defined as life-threatening organ dysfunction caused by a dysregulated host response to infection.


Make an object, person or area safe for unprotected personnel by removing, neutralizing, or destroying any harmful substance.


Microorganisms include all unicellular organisms and so are extremely diverse. Called Microorganism because they are de-tectable with a microscope and not necessarily harmful.

Sterile barrier system

A minimum package that minimizes the risk of ingress of microorganisms and allows aseptic presentation of the sterile con-tents at the point of use. (Source: EN ISO/TS 11139: 2018)

Resilience - microbial

Microbial resilience describes the rate of recovery after disturbance within the microbial community.

Resistance - antibiotic

Antibiotic resistance happens when germs like bacteria and fungi develop the ability to defeat the drugs designed to kill them. That means the germs are not killed and continue to grow. Infections caused by antibiotic-resistant germs are difficult, and sometimes impossible, to treat.

Protein Assay

The purpose of the protein assay (a validated measurement method) is to determine the amount or concentration of proteins.


Mathematically, Sterility Assurance Level (SAL) are probabilities. Medical device manufacturers design their sterilization processes for an extremely low SAL, such as 10−6, which is a 1 in 1,000,000 chance of a non-sterile unit.


A cross infection occurs when harmful germs transfer to a patient by way of another person or medical tools.


Types of germs are bacteria, viruses, fungi, and protozoa.

ID 50

The infective dose (ID) of microorganisms that will cause 50% of exposed individuals to become ill.
ID50 varies widely, from 10 organisms for Shigella dysenteriae to 106–1011 for Vibrio cholerae.


A colony forming unit (CFU) is defined as a single, viable germ that potentially produces a single colony.


Standard Infection Control Precautions : Standard precautions are meant to reduce the risk of transmission of bloodborne and other pathogens from both recognized and unrecognized sources.They are the basic level of infection control precautions which are to be used, as a minimum, in the care of all patients. Please refer to your national recommended SICPS.


Medium of transmission is blood.


The Decimal reduction time (D-value) is the time required at a specific temperature and under specific conditions to reduce a microbial population by one decimal, 90% respectively.


Mathematically the logarithm (log) is a term for a power to which a number can be raised e.g. 3 log or 103. In infection control log reduction conveys the efficacy of a process or product in reducing pathogens. A reduction of one log cycle equals a reduction of one decimal or a 90% reduction, hence takes the power down by one.


A process in which proteins lose the molecular structure, hence functionality, of their native state due to external stress (heat, organic- inorganic compounds).


Immunization is the process whereby a person’s immune system is stimulated to protect against subsequent infectious diseases, typically by administration of a vaccine.

Postexposure management

Postexposure management is an integral part of infection control in case health care personnel had unprotected exposure to an infectious source and may contain postexposure prophylaxis, psychological counseling etc.



International Organization for Standardization


European Standards (EN) are documents that have been ratified by one of the 3 European Standards Organizations, CEN, CENELEC or ETSI. They are designed and created by all interested parties through a transparent, open and consensual process. ... In essence, standards relate to products, services or systems

EN ISO 15883-1:2006/Amd 1:2014

Washer-disinfectors - Part 1: General requirements, terms and definitions and tests

EN ISO 15883-5:2005

ISO/TS 15883-5:2005 includes the test soils and methods that can be used to demonstrate the cleaning efficacy of washer-disinfectors (WD) according to the ISO 15883 series of standards.

EN ISO 15883-6:2011

ISO 15883-6:2011 specifies particular requirements for washer-disinfectors (WDs) intended for use when the level of assurance of disinfection that is necessary can be achieved by cleaning and thermal disinfection (A0 not less than 60) and does not require an independent automated record of critical processes to be kept.

EN ISO/TS 11139:2018

Previously ISO/TS 11139:2006; Now ISO 11139:2018
This document defines terms in the field of sterilisation of health care products including related equipment and processes

EN 13060:2018

EN 13060:2014+A1:2018 - This European Standard specifies the performance requirements and test methods for small steam sterilizers and sterilization cycles

EN ISO 17664:2017

EN ISO 17664:2017 specifies requirements for the information to be provided by the medical device manufacturer for the processing of a medical device that requires cleaning followed by disinfection and/or sterilization to ensure that the device is safe and effective for its intended use.

EN ISO 11607: 2019

This document specifies requirements and test methods for materials, preformed sterile barrier systems, sterile barrier systems and packaging systems that are intended to maintain sterility of terminally sterilized medical devices until the point of use.

EN 285:2015

Defines requirements and the relevant tests for large steam sterilizers primarily used in health care for the sterilization of medical devices and their accessories contained in one or more sterilization modules.

ANSI/AAMI ST 55:2016

ANSI American National Standards and The Association for the Advancement of Medical Instrumentation® (AAMI) Table-top Steam Sterilizers. This standard establishes minimum construction and performance requirements for small tabletop steam sterilizer in the USA

EN 1276:2019

The EN 1276 standard specifies a suspension test for establishing whether a chemical disinfectant or antiseptic has bactericidal activity. Bactericidal or antimicrobial products are products manufactured to control and fight against certain populations of pathogenic microorganisms.

EN 13704:2018

Chemical disinfectants. Quantitative suspension test for the evaluation of sporicidal activity of chemical disinfectants used in food, industrial, domestic and institutional areas.

White Papers

Transmission of Hepatitis B

Cross-transmission in the dental office: Does this make you ill?

Bacterial contamination of dental instruments

The concept of Sinner’s Circle

The purpose of disinfection

The chain of infection

What role does water play in the reprocessing

Drying – reason why

Inspection of instruments in the reprocessing cycle

Packaging instruments before sterilization

Wet packaging after sterilization: does this matter?

Continual germ reduction in the workflow

Storage of sterilized medical products

Corrosion of instruments is frequently underestimated

Short notes on transmission of infection

Sterilization with steam

Tracking instruments in the reprocessing chain

What’s about manual disinfection and the effectiveness?

Is disinfection or sterilization required?

Cleaning: A crucial step in the reprocessing workflow of medical devices and instruments

Thermal reduction – destruction of microorganisms

Logarithm, exponentiation and their connection to microorganisms