Croatia minor consent and assent requirements

Documents to prepare

Mandatory for a pediatric trial. Prepare one unified Croatian informed consent for the parent, guardian, or legal representative. It should contain the study information and signature section, explain the child's experience, and state that the child's wishes and refusal will be respected. Central Ethics Committee guidance provides for a signature field for one parent. If the child has no parent, the guardian or legally appointed representative signs.

Conditional by age. Prepare a separate Croatian Izjava o pristanku za sudjelovanje u kliničkom ispitivanju, meaning an assent statement for participation in the clinical trial, for each age band included in recruitment. Do not use one document for all children.

The blank parent and child documents are submitted in CTIS Part II under Subject information and informed consent form. They are versioned and dated but not signed at submission.

Croatian assent age bands

Ages 4 to 7

Use a short Croatian assent statement with simple illustrations, simple explanations, and font no smaller than 20. Explain who the child will meet, what will happen, what may hurt or feel uncomfortable, and that the child can say no or ask to stop.

Ages 8 to 11

Use a separate Croatian assent statement with simple illustrations, simple explanations, and font no smaller than 16. Explain the main procedures, burdens, choices, privacy, and the right to ask questions in language suitable for this age group.

Ages 12 to 14

Use a separate assent statement in an ordinary document format with simpler language. Explain the purpose, procedures, risks, benefits, alternatives, privacy, samples, pregnancy precautions where relevant, and voluntary choice at an age-appropriate level.

Ages 15 to 17

Use a separate assent statement in an ordinary format with simpler language. The detail may approach the adult document but should remain age appropriate. Address contraception, pregnancy testing, data, samples, long-term follow-up, and optional activities directly where relevant.

Information and assent process

The child must receive information suited to age and mental maturity from an investigator or trial-team member trained or experienced in working with children. Croatian law separately requires the informed-consent interview to be conducted by a physician or dentist who is the principal investigator or a delegated investigator.

A pediatric participant may take part only if they sign or give oral assent. If the child refuses or later wants to stop, the parent cannot force participation. Put this rule in the parent or representative document as well as the child-facing material.

Do not treat silence or failure to resist as assent. Record oral assent in the approved manner when a child is too young or otherwise unable to sign but can express a view. The protocol and recruitment procedure should describe how the team assesses understanding and documents the child's response.

Parent, guardian, and legal-representative consent

The parent or representative receives the full Croatian informed consent and signs after the consent discussion. Central Ethics Committee guidance describes a guardian or legal representative as a person appointed by a court to represent the child or person lacking capacity. That person need not be a relative or live in the same household.

Use the person's correct legal role. A caregiver, study partner, family member, or accompanying adult is not automatically the legal representative. Verify authority before enrollment and retain the appropriate evidence at the site.

The physician or dentist conducting the interview also signs and dates the consent. The parent or representative receives a signed copy. Routine electronic consent is not permitted under current Croatian guidance.

Main differences from the adult consent

The parent document should explain the child's procedures, risks, benefit prospects, alternatives, costs, insurance, data, samples, and withdrawal. It must also explain how assent will be sought, that the child's refusal is decisive, and what happens if the child reaches adulthood during participation.

Child documents should focus on what the child will experience and decide. Do not copy the parent document into smaller font. Separate required trial procedures from optional research and give the child age-appropriate DA and NE choices where the child's view is sought.

If pregnancy follow-up could involve a minor participant or a minor partner, prepare a separate representative consent and a separate age-appropriate assent for pregnancy follow-up. The Croatia pregnancy follow-up guide explains this use case.

Re-consent and changes in legal status

Mandatory when the participant turns 18. Obtain the participant's own adult informed consent for continued participation at the first appropriate opportunity after adulthood and full legal capacity. Do not rely indefinitely on the earlier parent consent and child assent.

Re-consent is also needed when new information could affect willingness to continue, when the approved document is materially revised, or when the participant's legal capacity changes in a way that changes the decision-maker.

For stored samples, Croatian guidance specifically requires participants who consented as minors to provide their own consent for continued storage and use when they become adults and gain legal capacity. The Croatia secondary use consent guide covers this transition.

Croatia-specific final checks

• The parent and all assent versions are in professionally translated and proofread Croatian.
• Every recruited age band has its own assent statement.
• Ages 4 to 7 use illustrations and font at least 20.
• Ages 8 to 11 use illustrations and font at least 16.
• Ages 12 to 14 and 15 to 17 use separate simpler-language versions.
• The parent document includes one parent signature field or the correct guardian or representative field.
• A capable minor also signs, and oral assent can be documented where appropriate.
• The parent's consent does not override the child's refusal or dissent.
• The interview and signatures are completed in person on paper by the parent or representative, capable child, and physician or dentist interviewer as applicable.
• Adult re-consent and sample re-consent are planned before the participant reaches 18.

Return to the Croatia CTIS hub for the complete Croatia guide set.