It depends on government regulations, as well ... SOME sick time is protected, where the company can't discipline you for using it ... But if you use more than that, even if you have a "bank" of it - the company may decide you're taking "too much", and discipline you in some way.
Unfortunately, this is where we are with medical care. I have a couple of ongoing medical conditions do I see 2 different doctors regularly. On occasion I've waited for 2 to 3 hours. I hate when it happens but there you have it.