Compliance Essentials for Texting Trial Participants

Texting is the most reliable way to reach trial participants, and the easiest place for a site to accumulate quiet compliance debt. Most of the risk isn't dramatic — it's a consent record nobody can produce, a message that reads like advertising, or PHI sitting in a coordinator's personal phone. Here's what to get right.

Consent to text is separate from study consent

Signing an informed consent form does not give you permission to send SMS. Under US telemarketing rules, recruitment texts to someone who hasn't agreed to receive them are the exposure point, and consent for recruitment messaging should be captured before the first message goes out.

Practical version:

• On every lead form, landing page, and paper screener, include an explicit opt-in checkbox with plain language: who is texting, about what, that message and data rates apply, and that they can reply STOP.
• Don't pre-check the box. Don't bundle it with "I agree to the privacy policy."
• Store the timestamp, the IP or staff member who captured it, and the exact wording shown. If you change the wording, keep the old version.
• For phone-call leads, read the opt-in aloud and log it in the contact record the same day.

If you inherited a list with no documented consent — a registry, an old referral spreadsheet — don't start texting it. Call or email first and capture opt-in properly.

Honor opt-outs immediately and everywhere

STOP, UNSUBSCRIBE, QUIT, and plain-English variants like "please stop texting me" all count. The failure mode sites hit most often is a participant who opts out of recruitment texts and then keeps getting visit reminders from a different system. Your opt-out needs to propagate across every tool that can originate a message, and someone needs to own checking that quarterly.

Keep a documented distinction between recruitment messaging and study-conduct messaging (visit reminders, safety follow-up) in your SOP, and get the ethics committee's view on where that line sits for your study.

Keep PHI out of the message body

Assume the message will be read on a lock screen by someone other than the participant. That rules out diagnoses, medication names, study indication, and lab results.

Safe pattern: identify your site, reference "your upcoming appointment" or "the study you asked about," and ask them to call. Unsafe pattern: "Reminder: your hepatic impairment study visit Thursday."

This is also why personal phones are a problem. Texts live in iMessage backups, in the carrier's records, and in whatever the coordinator's phone syncs to. Use a site-controlled number with retained, exportable logs.

IRB-approved language, verbatim

Any message that functions as recruitment — the first outreach, a re-engagement nudge, a "spots still open" follow-up — is recruitment material and needs approval. Submit your templates as a set, including character-limited variants, and resist the urge to improvise in the field. Free-text replies answering a participant's question are fine; broadcast messages are not.

Build the audit trail you'd want in an inspection

For each participant you should be able to produce, in under five minutes: opt-in source and timestamp, full message history with sender identity, opt-out date if applicable, and which approved template version each outbound message used. If that lives in three systems and a coordinator's memory, consolidate it before someone asks.

A short checklist

1. Explicit, unbundled, logged SMS opt-in on every intake path.
2. Business-hours sending windows and a documented frequency cap.
3. Site-owned number; no personal devices.
4. No PHI in message bodies.
5. Approved templates, versioned.
6. Opt-out honored across all systems within one business day.
7. Exportable message logs retained per your record-retention SOP.