Medical Devices Rules

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Author: Sofia Almpani

1 Medical Device Regulation

The Regulation (EU) 2017/745 of the European Parliament and of the Council of 5 April 2017 on medical devices, makes changes to the classification rules and conformity assessment processes for medical devices. According to the regulation the definition of medical device is:

Medical Device means any instrument, apparatus, appliance, material or other article, whether used alone or in combination, including the software necessary for its proper application intended by the manufacturer to be used for human beings for the purpose of:

  • diagnosis, prevention, monitoring, treatment or alleviation of disease,
  • diagnosis, monitoring, treatment, alleviation of or compensation for an injury or handicap,
  • investigation, replacement or modification of the anatomy or of a physiological process,
  • control of conception,

and which does not achieve its principal intended action in or on the human body by pharmacological, immunological or metabolic means, but which may be assisted in its function by such means. (Ref.: MDD; Article 1 (2) (a))

The new MDR presents a framework of risk-based classification, leading to risk-appropriate conformity assessment procedures. Annex VII of the Regulation sets out the classification criteria with new rules for the following four classes:

  • Class I - Generally regarded as low risk such as stethoscopes, bandages, etc. The devices are non-invasive. (Special cases: Class Is for sterile & Class Im for measuring function)
  • Class IIa - Generally regarded as low-to-medium risk devices such as a hearing-aid.
  • Class IIb - Generally regarded as are medium-to-high risk such as ventilators and intensive-care monitoring equipment.
  • Class III - Generally regarded as high risk such as balloon catheters and prosthetic heart valves.

Manufacturers of medical devices will need to declare the classification of their products (Annex VIII).

The CE marking on a medical device is a declaration from the manufacturer that the device complies with the essential requirements of the relevant European health, safety and environmental protection legislations laid out in the directives. The appropriate conformity assessment procedures for the CE marking, depending on the product’s class, are descriced bellow:

  1. Conformity Assessment & Technical File of the Medical Device - Annex VII
  2. Manufacturer appointing a European Authorized Representative (EAR) as in 93/42/EEC, Article 1 parag.2
  3. European Competent Authorities (ECA) as in 93/42/EEC, Article 14 for Class I
  4. Quality Assurance from Notified Body for Classes IIa,IIb,III
  5. Notified body Involvement for Classes Im, Is - Annex V, Article 3 parag.1.
  6. Type examination from NB for Classes IIb,III - Annex III
  7. Design Dossier Certificate in Full Quality Assurance for Class III - Annex II, parag.4

See also the flow charts that illustrate these conformity assessment routes for each class (page 6).

2 Formalization of Medical Devices Rules in PSOA

In this usecase, the classification rules and the conformity assessment procedures were formalized in PSOA RuleML. Moreover, data for specific medical devices (Facts) were added directly in PSOA (MedicalDevicesKB). The results were queried in PSOATransRun. Medical Devices Rules Queries (copy&paste-ready) can also be found here.

The formalization consists of four parts:

  • In the first part, (informal) categories were created based on the kind and the uses of the medical devices described in the regulation. The categories are indicated by three letters which denote the three levels of the categorization (page 1 in ClassificationAndMarketability).


% Rule 4 
   % Devices in contact with injured skin.
    Forall ?m (
	 :CategoryOfMedicalDevice(?m :N4a) :-
	  ?m#:MedicalDevice(:kind->:NonInvasive :use->:ContactInjuredSkin :specificCase->:MechanicalBarrier)
  • In the second part, the aforementioned categories are connected with the classification class they belong, according to the regulation (pages 2-5&7 in ClassificationAndMarketability).


%Classification Grouping
 %Class I
     Forall ?m (:IsClassifiedIn(?m :I) :- 
      Or(:CategoryOfMedicalDevice(?m :N1)
         :CategoryOfMedicalDevice(?m :N4a)
         :CategoryOfMedicalDevice(?m :I5a)
         :CategoryOfMedicalDevice(?m :I6b)
         :CategoryOfMedicalDevice(?m :A10a)
         :CategoryOfMedicalDevice(?m :A11)
         :CategoryOfMedicalDevice(?m :A13))
  • In the third part, the requirements for the conformity assessment for each class are described in order for a device to obtain the CE marking and be marketable (page 6 in ClassificationAndMarketability).


%Requirements for Class I
     Forall ?m (:DeclarationOfConformityInClass (?m :I) :-
         And(:IsClassifiedIn(?m :I)
             :ConformityAssessment(:device->?m :technicalFile->:Yes :vigilanceSystem->:Yes :harmonizedStandards->:No))
  • In the last part, medical devices facts were developed based on the list of codes and the corresponding types of devices under Regulation (EU) 2017/745. In cases where the codes don’t describe specifically a category other (random) coding is applied (e.g. DeviceR3a), while in cases where more than one category belongs in the same code, letters a,b,c are used (page 7). The fulfilled requirements concerning the Marketability (page 8) of the devices are chosen randomly.


%Requirements of MDN1204a: Class I, 2Yes, No ECA
:MDN1204a#:MedicalDevice(:kind->:NonInvasive :use->:ContactInjuredSkin :specificCase->:MechanicalBarrier)
:ConformityAssessment(:device->:MDN1204a :technicalFile->:Yes :vigilanceSystem->:Yes :harmonizedStandards->:No)

This usecase is an evidence that PSOA RuleML can express real-world regulations and PSOATransRun is suitable for KB development.

You can find the Index with all the files here.