Call Tracking for Healthcare Clinics: DNI, IVR, and the Full Attribution Loop

By Raman Soni, Head of Performance Marketing at ICG.

For IVF, dermatology, and hair transplant clinics, 60-80% of actual appointment bookings happen via phone. An agency that does not track calls is optimising for 20-40% of the conversion signal.

This post walks through how call attribution works: DNI, IVR webhooks, and the loop from ad click to phone call to CAPI.

Why calls are the conversion event most agencies ignore

Healthcare patients call. They call after seeing a Meta ad on Instagram while researching during lunch. They call after seeing a Google ad result for "best dermatologist near me". They call from the GMB listing. They call from WhatsApp profile messages.

Almost none of these calls are tracked by default. The pixel does not fire because the conversion happens offline. The Google Ads conversion log shows zero. The Meta Events Manager shows zero. The patient walks through your door, but the bid algorithm never learned that the ad worked.

How Dynamic Number Insertion (DNI) works

DNI assigns a unique phone number to each traffic source. The patient who clicks a Google ad sees a different number than the patient who comes from GMB or from a Meta ad. When they call, the call tracking system knows which channel sent them.

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Implementation: a JavaScript snippet on your landing page swaps the displayed phone number based on the UTM source. Meta clicks see Number A. Google clicks see Number B. Organic visitors see Number C. The IVR provider (Exotel, Knowlarity, Servetel, CallRail) maps each number to its source.

IVR webhooks and ad platform attribution

When an IVR system receives an inbound call, it fires a webhook. That webhook can be routed to Meta CAPI (as a Lead or Schedule event) and to Google Ads (as an Offline Conversion Upload). Without this routing, every call that converts is invisible to the bid algorithms.

The architecture: IVR call → IVR webhook → middleware (Beacon) → enrich with caller phone number, channel attribution, lead source → fire to Meta CAPI and Google OCU.

The missed call problem

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156 missed calls in 7 days. 49% of inbound. Each missed call is a patient who clicked an ad, decided to call, got no answer, and, at IVF prices, likely called the next clinic.

The breakdown reveals which channel's patients are being missed. In this account, Google Ads has the worst miss rate, 87%, suggesting either inadequate staffing during peak ad hours or a routing problem in the IVR setup.

The full loop: from ad click to call to CAPI

1. Patient clicks a Meta ad → lands on the page → sees Number A (DNI swap)

2. Patient calls Number A → IVR receives → forwards to clinic + fires webhook

3. Beacon receives webhook → enriches with caller identity, channel attribution, IP, user agent

4. Beacon fires to Meta CAPI (Lead event) and Google OCU (matching the original click ID)

5. Bid algorithms learn from the real conversion. Smart bidding tightens.

Without this loop, your bid algorithms are guessing. With it, every patient who picked up the phone counts towards Meta's and Google's optimisation.