"Left to Right" is a short story by American science fiction writer Isaac Asimov, featured in the short story collection Gold.
Robert L. Forward has created a device that will change whatever goes through it into mirror matter.
The other character argues that he will not be able to digest because his internal organs will be the wrong way round and his biochemistry altered, but Forward argues that he can just pass through it a second time.
He travels through, and checks his heartbeat and appendectomy scar (which are on the same side as before).
This article about a science fiction short story (or stories) published in the 1980s is a stub.