Readability Testing of Labelling and Package Leaflets in Europe

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Readability Testing of Labelling and Package Leaflets in Europe

In the European Union, pharmaceutical companies must meet more than clinical and manufacturing standards to gain marketing authorisation. They must also ensure that the package leaflet (PL) and labelling of their medicinal products are clear, legible, and easily understood by patients. This is where Readability Testing—or user testing—comes in. This essential regulatory requirement ensures that patients can understand how to take their medicine safely and effectively.

What is Readability Testing?

Readability testing, often referred to as user consultation, evaluates whether a package leaflet is clear, easy to read, and understandable to the target patient population. It is a legal requirement under Directive 2001/83/EC, and applies to all human medicinal products submitted through national, decentralised, mutual recognition, or centralised procedures in the EU.

The goal is to confirm that:
  • Users can locate important information.
  • Users understand the information once found.
Users can act on the information appropriately.

Why Is Readability Testing Important?

  1. Patient Safety
    2. Misunderstanding the dosage, route of administration, or side effects can have serious consequences. Clear leaflets help patients take medicines properly and avoid risks.
  1. Legal Compliance
    2. Article 59(3) of Directive 2001/83/EC mandates that package leaflets must reflect the results of consultations with target patient groups. Failure to meet this requirement can result in delays in marketing authorisation approval.
  1. Effective Communication
    2. Health literacy varies across populations. Readability testing ensures that all users—including elderly, visually impaired, or those with low literacy—can understand how to use the medicine.
  1. Efficient Review Process
    2. Submitting strong readability testing data increases the chance of first-pass approval by regulatory authorities like the EMA and national competent authorities.

When Is Readability Testing Required?

Readability testing is required:
  • For all new marketing authorisation applications.
  • When there are significant changes to the package leaflet (e.g. new safety warnings).
  • For line extensions or changes to product presentation that could affect understanding.
It is not required:
  • For purely administrative updates.
  • If a previously approved leaflet can be “bridged”—i.e., justified based on similarity to an already tested leaflet.

How to Conduct Readability Testing

Readability testing follows a structured, evidence-based process involving real users from the target population. According to the European Commission guideline (Rev. 1, 2009), the standard method involves:

Step 1: Prepare the Package Leaflet
  • Use the QRD template to draft the leaflet according to EU standards. Include:
  • Plain, clear language
  • Appropriate font (≥9 pt Times New Roman)
  • Logical layout with headings, bullet points, and white space
Step 2: Recruit Participants
  • At least 20 participants must be recruited who represent the medicine’s intended users. Avoid including healthcare professionals. Include individuals of varying:
  • Ages
  • Educational levels
  • Familiarity with medicines
Step 3: Design and Conduct the Test
  • Use a full-colour mock-up of the leaflet as it will appear in the market.
  • Ask at least 12-15 structured questions, covering key safety and usage information.
  • Questions should assess the ability to find, understand, and act on information.
Step 4: Measure Success
  • A test is considered successful if:
  • At least 90% of participants can find each piece of information.
  • Of those, at least 90% can understand and explain the correct action.
  • This equates to 16 out of 20 participants for each key question.
Step 5: Document the Results
  • Include the following in your regulatory submission:
  • Product description
  • Test protocol and participant demographics
  • Questionnaire and results
  • Summary of issues and changes made
  • Revised package leaflet

How to File Readability Testing Results

Readability testing documentation is included in the marketing authorisation application within Module 1.3.4 of the CTD
For centralized submissions via EMA:
  • Results should be in English.
  • A separate test may not be needed for each language version, but all translations must reflect the tested leaflet accurately.
For mutual recognition and decentralised procedures:
  • Bridging reports may be acceptable if you can demonstrate similarity in content, design, and user population.
Special Considerations
Visually Impaired Patients
The package must also include:
Braille on the outer packaging (product name and strength)
Alternative formats (large print, audio, digital) available upon request
Multilingual Leaflets
If multiple languages are used in one leaflet, they must be clearly separated, and user testing must be conducted in one representative language.

How Masuu Global Can Help You

At Masuu Global Quality and Regulatory Consultants, we know that crafting and testing package leaflets isn’t just a compliance task—it’s a patient safety issue. We offer:

  • End-to-end Readability Testing Services
  • QRD-compliant leaflet drafting and formatting
  • User recruitment and testing coordination
  • Bridging report development
  • Mock-up preparation and submission management
  • Regulatory strategy for multilingual and high-risk products

We align your submission with both EMA and national agency expectations, helping you reduce time-to-market and regulatory friction.

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