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    Software & AISoftware LifecycleSiMD /sim-dee/

    Software in a Medical Device

    Software embedded in or required to operate a hardware medical device.

    Reviewed by Christian Espinosa, Founder, Blue Goat CyberLast reviewed May 5, 2026

    Definition

    Software in a Medical Device (SiMD) refers to software that is embedded within, or required for, the operation of a hardware medical device - such as firmware controlling an infusion pump or imaging system.
    What the regulation says
    Software in a Medical Device (SiMD) is considered a component of a hardware medical device and is regulated as such, rather than as a standalone medical device. The FDA addresses this in its guidance on "Software as a Medical Device (SaMD): Clinical Evaluation," clarifying that SiMD falls under the regulatory framework of the device it enables. Similarly, under the EU Medical Device Regulation (EU MDR) 2017/745, SiMD is subject to the general safety and performance requirements (GSPRs) applicable to the overall medical device, as outlined in Annex I.

    What this means in practice

    Unlike SaMD, SiMD is regulated as part of the parent device. It is still subject to IEC 62304, cybersecurity requirements, and design controls.

    Examples

    • Firmware that controls the delivery mechanism and dosage calculations of an insulin pump is an example of SiMD.
    • Software embedded in an MRI machine that processes imaging data and controls the scanner's operations is considered SiMD.
    • The operating system and user interface software on a patient monitor that displays vital signs is an instance of SiMD.
    Common pitfalls
    • •Failing to integrate SiMD development and maintenance into the overall medical device's lifecycle management processes can lead to regulatory non-compliance.
    • •Overlooking the specific cybersecurity risks associated with integrated software can compromise the safety and effectiveness of the medical device.
    • •Treating SiMD with less rigor than standalone software regarding design controls and validation activities is a common mistake.
    • •Assuming that general software development practices are sufficient without adapting them to medical device regulations is a pitfall.
    • •Neglecting to update SiMD in response to new cybersecurity threats or operating system changes can lead to vulnerabilities and regulatory issues.

    Frequently asked questions

    SiMD is integral to the functioning of a hardware medical device and is regulated as part of that device. SaMD, in contrast, is software that itself constitutes a medical device and performs a medical function without being part of a hardware medical device.

    Cross-references

    Governed by

    Regulations or standards this term must comply with.

    Often confused with

    Distinct concept frequently mistaken for this one.

    Grouped by theme

    Primary references

    3 sources
    Link health: 3 verified· last checked 2026-06-20
    FDA·2IMDRF·1
    1. 1
      FDA Software Functions
      Verified
      FDAfda.gov
    2. 2
      FDA - AI/ML-Enabled Medical Devices
      Verified
      FDAfda.gov
    3. 3
      IMDRF - Software as a Medical Device
      Verified
      IMDRFimdrf.org

    Inline markers like [1] jump to the matching reference above.