Bridging Global Standards: A Deep Dive into ISO 23162:2021 and Laboratory Competence: Mastering ISO 23162:2021 technical requirements and quality management framework for globally comparable semen examination results
This article focuses on ISO 23162:2021, the international standard that specifies requirements and test methods for basic human semen examination. While the WHO 6th Edition provides the clinical manual, ISO 23162 provides the technical and quality management framework for laboratories to ensure their results are globally comparable. The release of ISO 23162:2021 marked a milestone in reproductive medicine, being the first dedicated international standard for basic semen examination. For clinics and laboratories, compliance with ISO 23162 is no longer just an option—it is a badge of technical competence and diagnostic reliability. This guide outlines the core specifications of the standard and how it integrates with modern CASA technology.
Chapter 1: The Unified Framework (ISO 23162 vs. WHO 6th)
ISO 23162 was developed in tandem with the WHO 6th Edition Laboratory Manual. The two documents are complementary:
WHO 6th Edition: Focuses on the biological and clinical aspects of sperm analysis (the "how-to" and clinical interpretation).
ISO 23162:2021: Focuses on the specification and test methods (the "technical requirements").
Together, they ensure that a semen analysis performed in Tokyo is identical in accuracy and methodology to one performed in Berlin or New York.
WHO 6th Edition: Focuses on the biological and clinical aspects of sperm analysis (the "how-to" and clinical interpretation).
ISO 23162:2021: Focuses on the specification and test methods (the "technical requirements").
Together, they ensure that a semen analysis performed in Tokyo is identical in accuracy and methodology to one performed in Berlin or New York.
Chapter 2: Core Technical Specifications for Test Methods
ISO 23162 sets strict requirements for the measurement of the four primary semen parameters. Every lab must validate their methods—whether manual or automated—against these criteria.
1. Sperm Concentration and Count
ISO 23162 mandates the use of improved counting methods to reduce the Coefficient of Variation (CV).
Requirement: Laboratories must account for the exact volume and depth of the sample.
CASA Advantage: Automated systems like the Nexus Dx1 utilize precision-manufactured fixed-depth counting chambers (10μm/20μm) as required by the standard to eliminate volumetric errors.
2. Sperm Motility Grading
The standard enforces the three-category classification system (PR, NP, IM) to minimize subjective differences between technicians.
Requirement: Assessment must be performed at 37°C ± 0.5°C.
CASA Advantage: Integrated heating stages ensure that motility classification is based on actual physiological activity rather than a sample's reaction to room temperature.
3. Sperm Morphology
Morphology remains the most complex parameter. ISO 23162 requires rigorous adherence to "strict" criteria (the Kruger criteria).
Requirement: Assessment of at least 200 spermatozoa and calculation of indices such as the Teratozoospermia Index (TZI).
1. Sperm Concentration and Count
ISO 23162 mandates the use of improved counting methods to reduce the Coefficient of Variation (CV).
Requirement: Laboratories must account for the exact volume and depth of the sample.
CASA Advantage: Automated systems like the Nexus Dx1 utilize precision-manufactured fixed-depth counting chambers (10μm/20μm) as required by the standard to eliminate volumetric errors.
2. Sperm Motility Grading
The standard enforces the three-category classification system (PR, NP, IM) to minimize subjective differences between technicians.
Requirement: Assessment must be performed at 37°C ± 0.5°C.
CASA Advantage: Integrated heating stages ensure that motility classification is based on actual physiological activity rather than a sample's reaction to room temperature.
3. Sperm Morphology
Morphology remains the most complex parameter. ISO 23162 requires rigorous adherence to "strict" criteria (the Kruger criteria).
Requirement: Assessment of at least 200 spermatozoa and calculation of indices such as the Teratozoospermia Index (TZI).
Chapter 3: The Role of Automated Systems (CASA)
ISO 23162:2021 explicitly recognizes the use of Computer-Aided Sperm Analysis (CASA) systems but adds a layer of responsibility for the laboratory:
Validation: Automated systems must be validated against standardized manual methods.
Algorithm Transparency: The system must be capable of distinguishing sperm cells from "round cells" or debris (nonspermatozoal elements).
Traceability: Data must be stored digitally, allowing for the review of trajectories and morphological classifications if a result is questioned.
Validation: Automated systems must be validated against standardized manual methods.
Algorithm Transparency: The system must be capable of distinguishing sperm cells from "round cells" or debris (nonspermatozoal elements).
Traceability: Data must be stored digitally, allowing for the review of trajectories and morphological classifications if a result is questioned.
Chapter 4: Quality Assurance and Standardization (IQC & EQC)
A significant portion of ISO 23162 is dedicated to Internal Quality Control (IQC) and External Quality Assessment (EQA).
IQC: Labs must perform regular checks using beads or stabilized sperm samples to ensure the equipment is not "drifting" in accuracy.
EQA: Participation in proficiency testing programs is required to compare the lab's performance with its peers globally.
Standardization: The standard emphasizes that using validated equipment (like Nexus CASA systems) reduces the need for constant manual recalibration, as the AI and hardware are pre-calibrated to the WHO/ISO benchmarks.
IQC: Labs must perform regular checks using beads or stabilized sperm samples to ensure the equipment is not "drifting" in accuracy.
EQA: Participation in proficiency testing programs is required to compare the lab's performance with its peers globally.
Standardization: The standard emphasizes that using validated equipment (like Nexus CASA systems) reduces the need for constant manual recalibration, as the AI and hardware are pre-calibrated to the WHO/ISO benchmarks.
Chapter 5: Standardized Reporting Requirements
According to ISO 23162, a professional semen analysis report is not just a list of numbers. It must include:
• Traceability Information: Sample collection time, liquefaction time, and temperature of analysis.
• Lower Reference Limits: Comparison against the WHO 6th Edition 5th centile values.
• Methodological Notes: Whether the analysis was manual or performed via a validated CASA system.
• Clinical Comments: Clarity on whether the sample was "complete" or if there were any processing anomalies.
• Traceability Information: Sample collection time, liquefaction time, and temperature of analysis.
• Lower Reference Limits: Comparison against the WHO 6th Edition 5th centile values.
• Methodological Notes: Whether the analysis was manual or performed via a validated CASA system.
• Clinical Comments: Clarity on whether the sample was "complete" or if there were any processing anomalies.
Summary Checklist: Achieving ISO 23162 Compliance
For a laboratory to be considered compliant with ISO 23162, it should look for the following in its diagnostic partners:
• Validated Hardware: Equipment that supports fixed-depth microfluidic analysis.
• Standardized Software: AI algorithms updated to the WHO 6th Edition criteria for morphology and motility.
• Environmental Integrity: Built-in temperature control to maintain 37°C.
• Data Integrity: Secure storage of analysis videos and results for auditing and LIS integration.
• Documentation: Clear manufacturer support for validation and quality control procedures.
• Validated Hardware: Equipment that supports fixed-depth microfluidic analysis.
• Standardized Software: AI algorithms updated to the WHO 6th Edition criteria for morphology and motility.
• Environmental Integrity: Built-in temperature control to maintain 37°C.
• Data Integrity: Secure storage of analysis videos and results for auditing and LIS integration.
• Documentation: Clear manufacturer support for validation and quality control procedures.
Conclusion: The Path to Precision
ISO 23162:2021 is more than a technical document; it is a roadmap to diagnostic excellence. By adopting technologies that are built with these international standards in mind, clinics can ensure the highest level of patient care, reduce laboratory error, and lead the way in the future of reproductive science.
Disclaimer: This guide is intended for educational and professional resource purposes. Laboratory accreditation should be sought through relevant national and international accreditation bodies.
relatedProduct: "nexus-dx1"
Disclaimer: This guide is intended for educational and professional resource purposes. Laboratory accreditation should be sought through relevant national and international accreditation bodies.
relatedProduct: "nexus-dx1"
References & Technical Resources
- ISO 23162:2021. Biotechnology — Requirements for evaluating the performance of quantification methods for nucleic acid target sequences — qPCR and dPCR. Geneva: International Organization for Standardization; 2021. Available at: https://www.iso.org/standard/74800.html