HIPAA and Accessibility Readers

Delete all the text 

Is there a requirement for the term to be announced correctly? Asking because technically there is no WCAG requirement for acronyms to be pronounced correctly by the screen reader. Screen reader users (at least, JAWS users) have the option to change how acronyms are pronounced on an individual basis (on their own computers) by using the Dictionary Manager. Users can override how specific words, phrases, and acronyms/initialisms are spoken.

If you do have a requirement you could break the textboxes up into separate textboxes to keep to the 150 character "limit."

But the 150 character limit is not a real hard limit. It is only a suggestion to keep run-on alt text from being a bad user experience (conciseness is good). Keeping to this limit could prevent learners from getting sufficient meaning if you really need more than 150 characters to get across the information. The goal for alt text is to be as short as possible but as long as necessary based on purpose and context.

Screen readers themselves don't truncate the alt text at 150 characters. Some of them may pause, breaking the alt text into segments, to give the user a break and decide when to move on, but no alt text is lost.

Also, it looks like your textbox has bullets in it. If you include alt text on a text box with bullets in it, it will break how those bullets are read to a screen reader. Screen readers are supposed to read bullets with specific contextual information ("list of 5 items, bullet _, bullet _ ... list end"). When you add alt text to a textbox with bullets, that text replaces the default semantic information that goes along with the bullets. 

In fact, this IS an actual WCAG requirement (bullet semantics - WCAG 1.3.1) whereas the acronym pronunciation is not.