Building an SMS Pre-Screening Flow for Clinical Trial Inquiries

A phone-based pre-screening call takes 12–18 minutes per patient and requires a coordinator to be available during business hours. An SMS pre-screening conversation completes in 3–5 minutes of elapsed time, runs at any hour, requires zero coordinator involvement for clearly ineligible patients, and delivers the coordinator a complete pre-screening result before they make a single phone call. This guide builds that SMS flow.

Which Questions Work in SMS Pre-Screening

SMS pre-screening is effective for binary yes/no eligibility questions — criteria the patient can answer definitively without clinical interpretation. The questions that work:

• “Are you between [age range] years old?” — Yes / No
• “Have you been diagnosed with [condition] by a doctor?” — Yes / No
• “Are you currently taking [disqualifying medication]?” — Yes / No
• “Have you participated in a clinical trial in the past [washout period]?” — Yes / No
• “Are you able to visit our [city] location approximately [X] times over [timeframe]?” — Yes / No

Five questions, each sent as a separate SMS, with the patient replying YES or NO. The conversation bot processes each response and routes accordingly.

The Branching Logic

Build two branches:

• Pass branch (all criteria met): “Based on your answers, you may be eligible for our study. I’ll flag your record as a priority — [coordinator name] will call you within one business day to discuss next steps. What is the best time to reach you?”
• Fail branch (any disqualifying answer): “Thank you for your responses. Based on what you shared, you may not currently meet all of our eligibility requirements. Our team will still review your information — sometimes there are exceptions. We appreciate your interest.”

The fail branch does not definitively disqualify — it reduces the coordinator priority, not eliminates the patient. Borderline cases still reach a human.

Platform Options for SMS Conversation Flows

• Twilio Studio: Twilio’s drag-and-drop conversation flow builder. No coding required. Build the branching logic visually. Cost: Twilio messaging rates + $0 for Studio (included).
• SimpleTexting: simpletexting.com — built-in automation workflows, easier interface than Twilio, higher per-message cost. Good for non-technical teams.
• TextMagic: textmagic.com — similar to SimpleTexting with good template management. HIPAA BAA available.

Integrating Pre-Screening Results into Your CRM

When a patient completes the SMS flow, the result (pass/fail + answers) should automatically create or update their CRM record. In Twilio Studio: add an HTTP Request widget at the end of each branch that posts the conversation data to your CRM’s API or a Zapier webhook. The coordinator opens the patient record and sees pre-screening results before making any call — zero re-asking of questions.

48-Hour Action List

1. Hour 1: Write your five pre-screening questions in plain patient language. Test each with a coordinator: “Could a patient answer this definitively with yes or no?” Remove any that require clinical interpretation.
2. Hour 2: Open Twilio Studio (console.twilio.com → Studio). Create a new flow. Build the five-question sequence using “Send Message” and “Gather Input” widgets for each question.
3. Hour 3: Build the pass and fail branch endings. Add a Zapier webhook at each branch endpoint to push results to your CRM.
4. Day 2: Connect the flow trigger to your inquiry form: new submission → Twilio initiates the pre-screening SMS conversation. Test end-to-end with your own phone number. Track pre-screening completion rate and pass/fail ratio weekly from launch.