MD or IVD software classification (part II)

Under the Medical Device Directive (MDD) and the In Vitro Diagnostic Medical Device Directive (IVDD), medical device software (MDSW) was generally considered to be low risk and, therefore, a low-class device. Specifically, MDD considered MDSW to be an active medical device, following rules 9 to 12 (Annex IX, Section III), with an outcome that could range from class I to class IIb. In practice, software was typically classified as a Class I MD. IVDD, instead, considered to be a “General/Other” IVD except if it was intended for evaluating the risk of trisomy 21, in which case it was in List B (Annex II).

With the MDR full implementation and the date of the IVDR implementation approaching on 26 May 2022, MDSW are likely to obtain a higher classification. In particular, stand-alone software receives more attention in the EU Regulation 2017/745 (MDR) and EU Regulation 2017/746 (IVDR).

Software classification rules under MDR and IVDR

The MDR contains a specific classification rule for stand-alone software: Rule 11 (Annex VIII). This rule states that:

“Software intended to provide information which is used to take decisions with diagnosis or therapeutic purposes is classified as Class IIa, except if such decisions have an impact that may cause:
-death or an irreversible deterioration of a person’s state of health, in which case it is in Class III; or
-a serious deterioration of a person’s state of health or a surgical intervention, in which case it is classified as Class IIb.

Software intended to monitor physiological processes is classified as Class IIa, except if it is intended for monitoring of vital physiological parameters, where the nature of variations of those parameters is such that it could result in immediate danger to the patient, in which case it is classified as Class IIb.
All other software is classified as Class I.“

In the IVDR instead, the classification rules are slightly different. In this regulation, software is classified according to the class of the device it is accompanying or influencing.In addition, the IVDR does not contain a specificclassification rule for stand-alone software.The IVDR Implementing Rule 1.4 (Annex VII) states that:

“Software, which drives a device or influences the use of a device, shall fall within the same class as the device. If the software is independent of any other device, it shall be classified in its own right.”

Additional MDCG guidance document for software classification

According to MDR rule 11, the classification for stand-alone software can range from class I to class III depending on the impact of the information provided by the software. Since this rule does not provide a literal interpretation. Therefore, to avoid the related legal uncertainty, the IMDRF risk framework is suggested to assist in the classification. This framework has been adopted for the MDR into MDCG 2019-11 which provides a table that facilitates device classification based on: (1) the significance of the information provided by the MDSW to a healthcare situation related to diagnosis/therapy; and (2) the state of healthcare situation or patient condition. Interestingly, class I does not appear in the table, suggesting that under the MDR class I, MDSW will be rare and software will tend to have a higher risk classification.

How EU MDR Rule 11a maps on the IMDRF SaMD risk framework — Figure 1. Source: BSI group. Software as a Medical Device (Baird and Cobbaert, 2020)

MDCG 2019-11 states that implementing rules (MDR Annex VIII, Implementing Rule 3.3, or IVDR Annex VII, Implementing Rule 1.4) should also be considered for orientation to find the correct classification of software that drives or influences the use of a device. Therefore, an MDSW that both achieves its intended purpose and drives or influences the use of another MD for a medical purpose is classified on its own, based on the intended purpose achieved. In such a case, however, the risk class shall not be lower than the risk class of the MD.

In this guideline, also implementing rules 3.5 and 1.9 (MDR Annex VIII or IVDR Annex VII, respectively) are considered to be relevant for all devices, which state:

“If several rules, or if, within the same rule, several sub-rules, apply to the same device based on the device’s intended purpose, the strictest rule and sub-rule resulting in higher classification will apply”

Difference between MDR/IVDR classification version IEC 62304 software classification

Besides the MDR and IVDR, there are additional standards to consider when classifying MDSW’s risk class. The IEC 62304 is a European harmonized standard and specifies life cycle requirements for the development of MDSW. IEC 62304 classification system focuses on safety and is independent of the classification systems in the MDR and IVDR.

In general, the MDR defines classes I, IIa, IIb, and III depending on the risk the device poses. Accordingly, the IVDR defines classes A to D, where class A includes the non-critical devices and class D the most critical devices. Software Safety according to IEC 62304 is divided into three classes:

Class A: If the software cannot cause any harm.
Class B: If the software can cause minor harm such as injuries.
Class C: If the software can cause major harm such as severe injuries or even death.

The software safety class determines the amount and specificity of required software documentation as follows:

Figure 2. Summary of requirements for MDSW based on IEC62304 standard.

Final remarks

Considering the growing number and complexity of MDSWs, its classification should be performed with care. The classification rules detailed in the MDR and IVDR provide the requirements that help manufacturers and agencies navigate a well-laid-out system. At the same time, the guidelines also encourage manufacturers to adopt continued data protection measures.

Ensuring precise classification, adequate clinical evidence, and appropriate risk mitigation procedures play critical roles in addressing and improving patient safety and device performance to successfully place a device on the market.

At AKRN Scientific Consulting SL, we are experts in MDSW. We can help manufacturers prepare or update the required documentation to fulfil the MDR or IVDR requirements to obtain or maintain the CE-mark.