More seriously, if following a grammatical rule causes confusion you can choose to ignore the rule (or, as would be the sane choice in the Buffalo situation, evade the rule by rewriting to avoid the issue).
General rule: don’t use the comma. If the sentence is ambiguous to the reader in a specific case, then either: add a comma, or rewrite your sentence to be less confusing.
For example, “Apples, oranges and pears” the “and” has the about the same count as the pause after “Apples”; pausing before the “and” feels like a stutter.
"We're having hot dogs, hamburgers, and peanut butter and jelly.
Especially in a medical setting where the aesthetics of a sentence are not close to as important as clarity.