Regulatory divergence of NIRS-based technologies: distinguishing cerebral oximeters and fNIRS devices under IEC 80601 standards

English

Abstract:

Near-infrared spectroscopy (NIRS)-based technologies have evolved into two distinct device categories with increasingly well-defined regulatory and clinical boundaries: cerebral oximeters and functional near-infrared spectroscopy (fNIRS) devices. This article by Zhao Jianjun and Li Zhenfang provides a comprehensive analysis of their divergent development pathways, with particular emphasis on the evolving requirements of IEC 80601-2-85 and IEC 80601-2-71.

Through a detailed historical and technical examination, the article clarifies how cerebral oximetry devices have become validated clinical devices for monitoring cerebral blood oxygenation, supported by standardised benchmarking and integration into routine perioperative and critical care practice. In contrast, it explains how fNIRS devices (despite their shared optical origins) have been reclassified as scientific research tools in the IEC standards due to limitations in signal interpretation, validation, and diagnostic specificity.

By addressing long-standing terminology overlap and inconsistent application of the NIRS designation across device types, the article highlights critical regulatory implications for classification, approval pathways, and clinical claims. It further outlines practical recommendations for strengthening regulatory clarity, improving awareness of international standards, and reducing misapplication risks.

Learning objectives:

After reading this article, readers should be able to:

• Distinguish between cerebral oximeters and fNIRS devices based on intended use, measurement principles, and regulatory scope.
• Explain how IEC 80601-2-85 and IEC 80601-2-71 define different validation and performance expectations.
• Identify regulatory and compliance risks arising from ambiguous terminology or unsupported clinical claims.
• Apply classification and standards’ selection principles when evaluating NIRS-based device submissions, labelling, and promotional materials.

About the authors:

Zhao Jianjun is an Expert Member of the National Technical Committee for Standardisation of Medical Electrical Equipment. He has extensive experience in the development, revision, and compliance-related technical research of international standards for medical electrical equipment. From 2023 to 2025, he led several special working groups, including TC10, TC103, and IEC/TC 62/SC 62D/JWG5, and oversaw the revision and updating of the international standard IEC 80601-2-71. Under his leadership, the 2025 edition revised and clarified a number of technical definitions and application statements that had evolved through earlier editions of the standard. The revised standard removed references that could be interpreted as supporting broad clinical diagnostic use of fNIRS devices in areas such as psychiatry, neurosurgery, and paediatrics, and more clearly distinguished the intended use, regulatory status, and application scope of fNIRS devices. The 2025 edition also addressed longstanding issues arising from the historical development of NIRS and fNIRS standards, including ambiguities relating to device classification, qualification, and application scenarios. In addition, he led international efforts to promote, interpret, and support the implementation of IEC 80601-2-71 and IEC 80601-2-85 worldwide.

Li Zhenfang (PhD), College of Engineering, China Agricultural University. Her research focuses on regulatory compliance frameworks, clinical access requirements, and the international standardisation of NIRS/fNIRS brain imaging equipment. She conducted a comprehensive review of the regulatory policies, registration and approval history, and industrial development of NIRS and fNIRS devices in Japan from 2000 to 2024, identifying three major stages in the evolution of industry oversight. Her work highlighted differences between technology adoption, regulatory qualification pathways, and standards development, including periods in which clinical applications, device classifications, and technical standards evolved at different rates. She has contributed to clarifying the regulatory and application boundaries between NIRS devices and research-oriented fNIRS devices, as well as the factors that have influenced industry practices over time. Based on this research, she proposed revisions to international standards aimed at improving consistency in device classification, intended use, and application guidance, including recommendations relating to the use of fNIRS technologies in specific clinical contexts. Relevant provisions were subsequently incorporated into IEC 80601-2-71:2025. She also leads international outreach, technical dissemination, and implementation activities supporting the adoption of IEC 80601-2-71 and IEC 80601-2-85 worldwide.

Specification:

11 pages plus covers, in English, supplied by email as a PDF.

This article will be published in the August 2026 issue of the Journal of Medical Device Regulation.