Based on DIN EN 554, validation is "a documented procedure for
furnishing, recording and interpreting the requisite results, in
order to demonstrate that a process continually meets the given
specifications". Expressed in simple terms this means:
validation is a complicated procedure during which a process is
investigated to establish whether it is continually executed, i.e.
also after validation, such that it meets all the
QUALITY REQUIREMENTS addressed to the process. Hence validation
of a sterilisation process furnishes proof of its suitability and
certifies its effectiveness. Validation must be documented.
The purpose of validation is explained as follows in draft DIN 58946-6 of
April 1998: "Validation serves to furnish documented proof of
the ongoing effectiveness of the sterilisation process under the
operating conditions prevailing at the installation site, using the
sterile items encountered in routine operation in their respective
packaging and with the reference loads used".
In principle all processes should be validated, in cases where each
product produced by the process cannot be checked for compliance with
the quality requirements (i.e. sterility in this case), as such a
test would render it unusable (i.e. unsterile). Therefore
EACH PROCESS to be used for sterilisation should also be validated.
Processes upon whose safe execution the health of people depends, hence also
sterilisation of medicinal products, must be validated at regular
intervals. In the pharmaceutical manufacturing industry validation
has been an established practice for a long time now.
DIN EN 554 entitled "Sterilisation of medical devices.
Validation and routine monitoring for sterilisation with
moist heat" stipulates, inter alia, requirements for monitoring
steam sterilisation of medical devices. In the context of this
standard and of the Medical Devices Ordinance (MPBetreibV), medical
devices are all devices that have been manufactured while taking into
account the provisions of MPG and which for this reason must have a
CE mark and possibly a 4-digit identification number affixed to them.
This definition will in the future apply to almost all the sterile
supplies processed in the CSSD. Furthermore, the steriliser itself is
also classified as a medical device and must be operated in
accordance with MPG and MPBetrreibV.
MEDICAL DEVICES OPERATOR ORDINANCE of June 29, 1998 states in Section 4, Para. 2:
"Cleaning, disinfection and sterilisation of medical devices
must be carried out with validated processes while observing the
manufacturer's instructions, so as to ensure that the safety and
health of patients, users or third parties are not compromised".
Since an ordinance has a legal character, a different procedure is adopted
from that described for cases of violation of a law, and a sentence
will be passed by judges if this violation would endanger the safety
and health of patients.
A process which is to be validated must demonstrate proof that it is
always executed in the same manner within defined limits. Validation
must have a basis, e.g. a standard. Processes to be validated should
be (fully) automatic.
Processes that are not reproducible, i.e. run differently in each case and thus
unpredictably, cannot be validated. Processes that do not comply with
the requirements specified in the standards governing them cannot be
validated on the basis of these standards.
Validation can be carried out by anyone who possesses the necessary expertise
and reliability, meets the prerequisites and disposes of appropriate
means and calibrated measuring equipment for proper execution of
Validation confers a whole range of advantages:
- The thermoelectric testing conducted for performance assessment is an exact physical method in which the measuring instruments and sensors used are checked for suitability immediately prior to testing.
- The process complies with DIN EN 554.
- The result is quickly available.
- During the performance assessment it is not only established whether the process is safe, but rather just how safe.
- A large part of the entire surroundings of the steriliser is taken into consideration during evaluation.
- The entire testing procedure is carried out in the CSSD.
If conditions have remained unchanged, thermoelectric testing of the
sterilisation process should be conducted once yearly with previously
calibrated sensors. If conditions have changed, a performance
assessment must be carried out again even before one year has elapsed.
1 This articles focuses in particular on the general principles of validation. In the next edition of Central Service the individual steps needed to implement validation will be outlined based on the example of a case.