1. Software Functions

• Main Functions (主たる機能)
• All functions affecting the intended use are defined as main functions. The underlying principles, descriptions, specifications, and test methods should be explicitly stated in the application dossiers.

• Additional Functions (付帯的な機能)
• Functions that do not affect the intended use of the medical device and are equivalent to those of predicate devices are considered additional functions. Principles should be described in sufficient detail to allow RCBs to verify equivalency to predicate devices. If no predicate devices with equivalent additional functions can be identified, the device would fall outside the scope of certification and be subject to PMDA review. It is recommended to check the "List of Additional Functions for Specified Controlled Medical Device" (指定管理医療機器の付帯的な機能のリストについて) in search for existing additional functions during application preparation.

2. Inappropriate Examples

Example 1: Human-Provided Service Misclassified as Software Function

• Generic Name:
  Software for general-purpose imaging system workstation (70030012)
• Issue:
  A function for uploading data to the cloud for further processing was claimed in the application. However, investigations revealed that data was manually processed by human experts, instead of by software.
• Result:
  The certification was withdrawn because the product lacked an actual main function as a medical device.

Example 2: Unverified Pathological Image Processing

• Generic Name:
  Software for general-purpose imaging system workstation (70030012)
• Issue:
  A function for pathology whole-slide image processing was based on a principle different from standard MR/CT image processing. Its equivalency and performance could not be verified against existing processing technology.
• Result:
  Functions such as image enhancement for diagnosis were deemed outside certification standards. The certification was maintained only after revising the descriptions to limit the software to Class I-equivalent additional functions, such as basic zooming and contrast adjustment

Example 3: Unproven Image Conversion Technology

• Generic Name:
  Software for radiation planning (40887003)
• Issue:
  A function to convert MR images into simulated CT images lacked evidence that the resulting images were reliable for further processing. Furthermore, no predicate device with similar functions was confirmed, meaning the product was not substantially equivalent to predicate devices.
• Result:
  The specific function was deleted from the product to maintain the certification.

Example 4: Clinical Significance Not Established

• Generic Name:
  Software for diagnostic X-ray imaging system workstation (40935012)
• Issue:
  A function intended to calculate bone density indices from chest X-ray images used a calculating principle different from established methods. Its clinical significance was unproven, and there were no predicate devices. It exceeded the established scope of the certification standards.
• Result:
  Since the product had no other main functions, the certification was withdrawn.

3. Other Information

• The execution of this notification will begin on November 2nd, 2026.
• Full Revision of "Examples of Descriptions in Marketing Approval (Certification) Applications and Technical Dossiers for SaMD" has been published (reference 2). Manufacturers should refer to this document from November 2nd, 2026.
• For certified SaMD products, manufacturers should conduct a self-assessment to ensure that the main and additional functions are within the certification scope and take appropriate actions, such as applying for partial changes if necessary. Any uncertainties should be discussed with RCBs.
• Since many of the inappropriate cases identified were related to Software for general-purpose imaging system workstation and General-purpose imaging system workstation, these generic names are now excluded from the application of the "List of Additional Functions for Specified Controlled Medical Device (Part 7)" is no longer applicable for these generic names.

Understanding a new market often requires both local knowledge and regional experience. With our Japan local offices in Osaka & Yokohama and 26+ years of experience across Asia Pacific, Qualtech supports medical device companies in navigating market regulatory requirements and evaluating growth opportunities. Contact us to discuss your plans for the Japan region.

References

1. Complete Revision of "Handling in Applications for Marketing Certification of Medical Device Software for Optimizing the Description of Main Functions and Ancillary Functions"
2. Complete Revision of "Examples of Descriptions in Application Forms and Attached Materials for Marketing Approval (Certification) of Medical Device Software"