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    SaMD vs SiMD

    Software as a Medical Device vs Software in a Medical Device

    SaMD and SiMD describe how medical device software is packaged and regulated. SaMD is standalone software performing a medical purpose. SiMD is software embedded in or required to operate a hardware medical device. The distinction drives which regulatory framework, submission path, and post-market obligations apply.

    IMDRF definition
    Software intended to be used for medical purposes that performs those purposes without being part of a hardware medical device
    Software that is embedded within, or required for, the operation of a hardware medical device
    Regulated as
    A standalone medical device in its own right
    A component of the parent hardware device (regulated together)
    Typical form factor
    Mobile app, cloud service, desktop application
    Firmware, embedded control software, on-device UI
    Runs on
    General-purpose computing platform (phone, PC, cloud) not itself a device
    Dedicated device hardware or a hardware platform that is itself a device
    Primary lifecycle standard
    IEC 62304 (applies to both, but SaMD is where it is most visible)
    IEC 62304, combined with IEC 60601-1 or IEC 61010 for the hardware
    Risk framework
    IMDRF SaMD categorization (I to IV) based on healthcare situation and information significance
    ISO 14971 applied to the whole device; software safety class per IEC 62304
    US FDA submission unit
    Separate 510(k), De Novo, or PMA on the software itself
    Part of the hardware device submission
    EU regulation
    MDR or IVDR classification rules apply directly (Rule 11 often relevant for SaMD)
    Assessed as part of the parent device conformity assessment
    Cybersecurity obligations
    Section 524B applies if connected; premarket cybersecurity documentation, SBOM, vulnerability management
    Same 524B obligations flow through the parent cyber device
    Change control
    AI/ML PCCP available to pre-authorize model updates without a new submission
    Software changes governed by device change control; can require new submission if safety or effectiveness affected
    Examples
    Diabetic retinopathy screening app; stroke triage cloud service; ejection fraction estimator
    Infusion pump firmware; MRI console software; ventilator control software
    Common misuse
    Treating a wellness app as SaMD when it makes no medical claim
    Labeling embedded firmware as SaMD to avoid parent-device change control

    When to use which

    Choose SaMD

    Classify as SaMD when the software achieves its medical purpose on its own and does not require specific hardware to perform that purpose. General-purpose platforms (phones, PCs, cloud) do not count as the hardware medical device.

    Full SaMD page
    Choose SiMD

    Classify as SiMD when the software is designed to run on, control, or be embedded in a specific hardware medical device, and the device cannot function safely without it.

    Full SiMD page

    Frequently asked questions

    Yes. A connected insulin pump has SiMD (pump firmware controlling actuation) and often a companion SaMD (a phone app calculating and recommending bolus doses). Each component follows its own classification path, with the SaMD portion typically requiring its own submission.
    Comparison built from the sourced definitions and FAQs on the linked term pages. MedTech Terms is a vendor-neutral community resource sponsored by Blue Goat Cyber. Definitions are written for educational use and are not legal or regulatory advice.