Overview
ISO 20836:2021 - "Microbiology of the food chain - Polymerase chain reaction (PCR) for the detection of microorganisms - Thermal performance testing of thermal cyclers" specifies requirements for the installation, maintenance, temperature calibration and temperature performance testing of thermal cyclers, including both standard block-based and real‑time (heated‑chamber) thermal cyclers. Although established for food‑chain microbiology, ISO 20836:2021 is applicable to environmental, human/animal health, forensic and other PCR‑based testing domains. The standard defines a physical measurement method with metrological traceability and measurement uncertainty suitable for ISO/IEC 17025 laboratories.
Key topics and technical requirements
- Installation and maintenance: guidance for correct siting, operation and routine upkeep of thermal cyclers to ensure reliable PCR performance.
- Temperature calibration and performance testing: procedures to measure block or chamber temperature directly (sensors in block or tubes) and to evaluate conformity with laboratory specifications.
- Performance metrics: definitions and measurement of temperature profile, temperature uniformity, ramp rate (heat/cool rate), overshoot/undershoot, minimum/maximum/average temperatures and transition characteristics.
- Test program and environmental conditions: requirements for a structured performance testing programme, controlled environmental conditions and documented test procedures.
- Metrological traceability and uncertainty: requirements to link measurements to national/international standards and to report measurement uncertainty in line with GUM (ISO/IEC Guide 98‑3).
- Compliancy and optical testing: methods for compliance testing and optical performance checks relevant to real‑time PCR instruments.
- Annexes and examples: informative annexes covering sensor locations, a universal temperature protocol, compliancy procedures and sample temperature profiles/reports.
Practical applications
- Validate that a thermal cycler is suitable for specific PCR assays (food pathogen detection, qPCR diagnostics).
- Establish acceptance criteria and periodic verification for laboratory equipment under quality systems (e.g., ISO/IEC 17025).
- Support purchasing decisions and vendor acceptance testing for new instruments.
- Troubleshoot PCR amplification variability related to thermal performance.
- Provide documented evidence for audits, accreditation and regulatory compliance.
Who should use ISO 20836:2021
- Molecular biology and microbiology laboratories (food safety, environmental, clinical, veterinary, forensic).
- Quality managers, laboratory accreditation specialists and technical leads.
- Calibration and service laboratories performing thermal cycler validation.
- Thermal cycler manufacturers and OEM service teams.
Related standards
ISO 20836:2021 helps laboratories and manufacturers ensure reliable PCR results by defining robust, traceable methods for assessing and maintaining thermal cycler performance.
Open preview (PDF)Microbiology of the food chain — Polymerase chain reaction (PCR) for the detection of microorganisms — Thermal performance testing of thermal cyclers
