The psychology of kit return: What drives completion?

Genetic testing has become a core component of patient identification and stratification in modern clinical trials, particularly in rare disease and precision medicine programs. Direct-to-patient testing models are now widely used to expand reach, reduce site burden, and accelerate eligibility assessment.

Despite these advances, a consistent challenge remains across programs: a meaningful proportion of participants who express initial interest do not progress to completed testing. Eligibility without activation is a false signal of demand, and small drops at this stage compound into months of delay and millions in added recruitment cost.

This pattern is often approached as an operational optimization problem. In practice, completion rates are shaped earlier in the participant journey, at the point where individuals evaluate whether to translate interest into action.

Across multiple studies, once a participant has requested a kit, return rates are typically high. The more significant variability occurs upstream, particularly between eligibility confirmation and kit ordering. This stage functions as the primary conversion threshold, where participant intent is tested against perceived effort, relevance, and trust.

Kit return rates therefore reflect cumulative decisions made throughout the journey rather than performance at a single step.

Where participant conversion is most sensitive

Participant flows for genetic testing in trial identification are structurally consistent: initial sign-up, onboarding and consent, eligibility determination, kit ordering, and kit return.

Early engagement tends to be strong. Most participants who sign up begin onboarding, and a majority complete it. Eligibility rates among those who complete onboarding are typically high.

The largest variability emerges after eligibility is established. Kit ordering rates can range widely across studies, while kit return remains comparatively stable once a kit has been requested.

This concentration of variability at the activation stage has material implications for trial timelines and cost. Lower conversion from eligibility to action requires higher top-of-funnel volume, extends recruitment periods, and increases cost per enrolled participant. These effects are amplified in rare disease settings where patient populations are constrained.

Participant decision-making at the point of activation

The transition from eligibility to kit ordering represents a shift in how participants engage with the study. At this stage, they are no longer wondering whether they qualify, but whether participation is worth their time and effort. Several factors consistently influence this decision.

Perceived effort relative to expected value

Participants assess the total burden of participation, which involves time, attention, administrative steps, and the cognitive effort required to understand what is being asked.

This is weighed against expected value, which may include access to a trial, potential clinical insight, or contribution to research. When value is not clearly articulated or does not feel personally relevant, even low levels of effort can deter progression.

In a survey on participants who signed up to the Sano platform to pre-screen into rare disease programs, several individuals expressed a desire to make an impact, often mentioning they wanted to ‘help research’ and ‘contribute meaningfully’ by participating in studies.

Clinical urgency and perceived treatment opportunity

Disease context materially shapes participant behavior. Participants managing progressive, severe, or poorly treated conditions are more likely to proceed through testing, particularly when participation is associated with a credible path to intervention. Genetic testing in this context is not viewed as exploratory. It is tied to potential access.

This includes:

• Eligibility for a targeted trial
• Identification of a genetic subtype linked to treatment
• Entry into a care pathway that was not previously available

In contrast, where disease burden is lower, stable, or where the link between testing and actionable outcomes is less clear, urgency is reduced. Participation is more easily deprioritized, even when initial interest is high.

This dynamic is especially pronounced in rare disease populations, where patients and caregivers are often highly informed and actively evaluating opportunities. The perceived proximity to treatment meaningfully affects follow-through.

Clarity and process legibility

Ambiguity introduces friction at each step of the journey. Participants are less likely to proceed when the process is difficult to interpret or when next steps are not immediately clear.

This includes uncertainty around:

• What actions are required
• How long each step will take
• What outcomes to expect after testing

High-performing programs reduce this uncertainty by making the pathway explicit and predictable. In a survey on participants in successful studies supported by Sano, 85% of participants rated platform instructions as clear or very clear.

Personal relevance and clinical context

Engagement is higher when participants can situate the study within their own clinical context. This includes understanding:

• How the study relates to their condition
• Whether results may inform treatment decisions
• What participation could enable in terms of access to trials or care pathways

In rare disease populations, where patients are often well-informed and actively seeking options, relevance is a primary driver of follow-through.

Commitment formation at consent

Informed consent functions as a key commitment point within the journey. Participants who complete consent are significantly more likely to continue to subsequent steps.

The quality of this interaction influences whether participants internalize the purpose and implications of the study. Consent processes that emphasize comprehension and relevance tend to support higher downstream conversion.

Continuity and momentum

Participant progression is sensitive to breaks in continuity. Delays between steps, lack of follow-up, or unclear transitions can result in disengagement even among initially motivated individuals.

Maintaining momentum requires coordinated communication and clear sequencing of actions.

Trust and data considerations

Participation in genetic testing involves sharing sensitive health information and engaging with uncertain outcomes. Trust in the study sponsor, the platform, and the data handling process influences willingness to proceed.

Transparency around study objectives, data use, and expected outputs supports sustained engagement across the journey.

Implications for study design and execution

Improving completion is primarily an upstream experience design problem rather than a downstream operational one.

Fragmented vendor models often fail because recruitment, testing, and engagement sit across disconnected systems. This creates breaks in the participant journey, including inconsistent messaging, repeated data entry, unclear next steps, and poor visibility into drop-off. Eligible participants disengage before activation.

Integrated approaches align these components within a single system, creating a continuous and interpretable participant experience. This continuity directly improves conversion from eligibility to active participation.

Sponsors should consider the following strategies for enhancing participant experience and conversion:

• Prioritize activation as a core metric: Conversion from eligibility to kit ordering has a disproportionate impact on overall enrollment efficiency.

• Design onboarding for comprehension, not just compliance: Early-stage interactions shape participant interpretation of effort, value, and trust.

• Reinforce relevance throughout the journey: Participants reassess their decision at multiple points. Ongoing contextualization supports continued engagement.

• Reduce friction across transitions: Operational simplicity and clear instructions directly influence whether participants proceed.

• Maintain continuity through structured follow-up: Consistent communication helps preserve momentum between steps.

Why this matters in rare disease trials

In rare disease programs, each participant represents a significant proportion of the addressable population. Losses early in the funnel are not easily offset by increased recruitment.

Improving conversion through the activation stage leads to:

• More complete identification of eligible participants
• Shorter enrollment timelines
• Lower recruitment costs
• More robust and representative datasets

These outcomes directly affect both trial feasibility and downstream clinical impact.

In practice, kit return rates are the result of earlier decisions shaped by clarity, relevance, effort, and trust. Designing effective genetic testing flows therefore requires aligning operational execution with participant decision-making at each stage of the journey. Participants who feel supported and informed are more likely to contribute to rare disease research and, in turn, gain access to potentially life-saving therapies.