Most advertisers can build audiences from site visitors, upload customer lists and let the algorithm find lookalikes. A clinic cannot treat patient intent that freely. Google's personalized advertising policy blocks targeting based on health conditions, which means a person who read your page about diabetes care or physical therapy after surgery cannot be followed around the web with condition specific ads. Certain categories, such as addiction treatment and some pharmacy offers, also need third party certification before ads run at all.
Privacy rules reach into your tracking code
Federal guidance on online tracking technologies warns that pixels on pages where people book visits, describe symptoms or log into a portal may transmit protected health information to ad platforms. Many medical groups quietly removed tags after reading it and then found their accounts bidding blind. The fix is not to track nothing. It is to track the right events on the right pages, keep form contents and diagnoses out of the data sent to Google, and bring scheduled appointment counts back in a way your compliance officer can sign off on.
Clicks that look like patients but are not
Healthcare terms pull a surprising amount of research traffic: nursing students, job seekers looking for medical assistant roles, people checking symptoms at midnight with no intention of booking, and patients of a nearby hospital system looking for their own chart login. Each of those needs a negative keyword or a tighter match type, or the account pays for curiosity rather than visits.