BS EN ISO 20836:2021 pdf free download – Microbiology of the food chain – Polymerase chain reaction (PCR) for the detection of microorganisms一Thermal performance testing of thermal cyclers.
e) the laboratories performing one or more steps in the chain supply evidence for their technical coin pet en ce.
NOTE Calibration laboratories fulfilling the requirements of the ISO/IEC 17025 are considered to be competent. A thermal cycler calibration certificate bearing an accreditation body logo from a calibration laboratory accredited to the ISO/IEC 17025 is sufficient evidence of traceability of the calibration data reported.
6.4 Temperature performance testing method
6.4.1 General
This performance testing method is intended to determine the thermal cycler temperature parameters that influence the outcome of the PCR and RT PCR. It can be used to perform a temperature performance test on both PCR and real-time PCR thermal cyclers.
An example of a test and compliancy report is given in AnnexE.
6.4.2 Principle
The temperature is measured by temperature sensors directly in the reaction block in block-based thermal cyclers or inside the reaction vials in reaction-chamber-based thermal cyclers, in order to achieve an adequately low measurement uncertainty. The measurement is performed over the complete reaction temperature range, including at least a minimum, maximum and middle temperature. lithe thermal cycler has a heated lid, the measurement shall be performed with the heated lid closed and operating, when physically possible.
6.4.3 Equipment
6.4.3.1 Thermal cycler
The thermal cycler shall be checked, before the performance test, to be functional.
The ventilation openings shall be clean and not obstructed, allowing free air circulation.
6.4.3.2 Temperature measurement system
The temperature measurement system shall meet at least the following criteria:
a) multi-sensor system with an adequate number of temperature sensors to measure simultaneously in at least the number of required wells (see 6.4.5.1), allowing to measure uniformity;
b) capable of recording the heated lid temperature with at least one temperature sensor (when physically possible);
I) response time of the sensors  1 s.
The temperature performance test unit shall be calibrated in a metrological traceable manner at
regular intervals according to a predefined programme.
6.4.4 Environmental conditions
The performance test shall be performed at suitable environmental conditions that do not invalidate the results or adversely affect the required quality of the performance test.
NOTE The performance testing environmental conditions typically correspond to the environmental conditions required for operation of the thermal cycler.
6.4.5 Procedure
6.4.5.1 Temperature sensor locations
If the performance testing method of this document is used as a metrological traceable temperature calibration, as a conformity test or as a reference method the following combination of criteria shall apply.
For each heating block-based or heating-chamber-based thermal cycler the following criterion shall be met:
— the temperature sensors shall be located evenly distributed over the reaction block or chamber in at least 12,5 % of the wells for reaction blocks or chambers >= 96 wells or 12 wells for reaction blocks or chambers > 96 wells.
For rectangular heating block-based thermal cyclers the following additional combination of criteria shall be met:
a) the locations shall include four corner locations for heating blocks > two columns or rows of wells or two corner locations for heating blocks >= two columns or rows of wells;
b) the locations shall include at least one edge location for each edge of the heating block  six wells;
c) the locations shall include at least two central locations for heating blocks> 18 wells and at least four central locations for heating blocks > 48 wells.
For thermal cyclers that contain independent heating and control units, each of the units shall be tested.