The first validation of a steam sterilisation process is divided into the
following steps given here by way of example:
During commissioning tests are conducted to establish whether the
preconditions for successful sterilisation are met. These include,
inter alia, testing whether the steriliser meets the requirements for
installation and connection and whether the operating materials
fulfil the requirements of the steriliser manufacturer. To save time
and cut costs, commissioning should be omitted if a steam
sterilisation process is not being validated for the first time and
if no changes of relevance to commissioning have occurred since the
time of first validation.
The vacuum test furnishes proof that vacuum tightness of the system is
still assured also following introduction of the temperature sensors into
the steriliser chamber. In the event of impermissible deviations, their
cause must be elucidated and the fault eliminated before further
tasks can be carried out.
CALIBRATION of the pressure and temperature sensors used during validation
Calibration serves to prove and document that the sensors are functioning
within the permitted tolerances. Calibration must be performed using
high-quality test equipment which for its part has also been
calibrated. The validity of the test equipment used for calibration
should be proven and noted in the documentation.
Recording the EMPTY CHAMBER PROFILE
The empty chamber profile is a temperature measurement with which the
temperature distribution can be documented at different measuring points
in the non-loaded chamber. Recording of the empty chamber profile can be
omitted in agreement with the customer.
Definition of the REFERENCE LOAD (sample load)
The reference load is the load used for validation.
It reflects the most difficult combination of items to be sterilised (DIN EN 554).
The reference load is the load which corresponds to a large number of different
loads otherwise normally used. But due to the large number of sterile items and
loads encountered in the CSSD, in practice there are several reference loads with
which a process is validated. Later, all sterile supply loads will be based on the
validation of these reference loads. The reference loads are generally defined in
consultation with the person responsible for the CSSD. It is unusual for the
validation expert alone to define the reference loads, and this should be rejected.
Based on DIN EN 554 the performance assessment denotes the
"search for and furnishing of proof that the commissioned system produces
acceptable products when operated according to the process specifications".
The assessment performance evaluates the main body of the building,
including installation situation and provision of operating
materials, the steriliser, sterilisation process, items to be
sterilised, packaging and correct operation of the steriliser. Within
the framework of the performance assessment, tests are conducted at
several locations in the reference load to establish whether the
sterilisation temperature has been reached and remains constant
within certain limits during the entire sterilisation phase.
Moreover, compliance with the sterilisation time is checked. All
results must be documented and evaluated. The performance assessment
is the most expensive and onerous part of validation.
The validation documentation contains reports on commissioning and on the
performance assessment. It can be compiled entirely or partially using software.
The scope of the documentation is defined by the validation expert in consultation
with the customer, e.g. the CSSD management. The documentation is checked by the
expert for completeness on finishing validation.
RELEASE OR BLOCKING of a sterilisation process
Following successful validation the processes are released by the expert,
hence they may now be used. The validation report is handed over to the
customer and depending on how the validation test laboratory is organised,
a copy of the validation report may be forwarded to the head of the test
laboratory for additional evaluation and final release of the process.
Insights from the report are incorporated into training programmes for
validation experts and are important especially in respect of the knowledge
gained for definition of reference loads.
If the validation outcome for a process does not meet the requirements, the
process is deemed not to be validated in respect of the reference load and is
blocked by the expert, who duly communicates this to the person responsible
for the CSSD. The responsibility for ensuring that the respective combination
of process and load is not used is borne by the CSSD management.
Validation cannot be conducted at the premises of the steriliser manufacturer,
because the conditions prevailing there are not those encountered at the site
of operation. These include, e.g. the installation situation and provision of
operating materials which are to be evaluated during commissioning. Furthermore,
it is absolutely necessary during validation that the sterile supplies encountered
at the site of operation, the packaging and steriliser load be included in the
with kind permission of|
How is validation of a steam sterilisation process conducted in the CSSD?
COMMISSIONING tests whether the preconditions for successful sterilisation are met.
THE VACUUM TEST furnishes proof of vacuum tightness after introduction of the temperature sensors.
CALIBRATION documents that the sensors are functioning within permissible tolerances.
THE EMPTY CHAMBER PROFILE shows the temperature distribution at different measuring points in the non-loaded chamber.
THE REFERENCE LOAD is the most difficult combination of items to be sterilised; this is the load used for validation.
THE PERFORMANCE ASSESSMENT furnishes proof that the commissioned system produces acceptable products.
THE VALIDATION DOCUMENTATION contains reports on commissioning and performance assessment.
RELEASE OR BLOCKING of a process depends on whether validation has been successful or not.
Is it possible to validate a sterilisation process already at the manufacturer's premises?