Can a physician wear a hospital ID on shabbat in an area without an eruv? It is impossible to enter the hospital without the id. The physician is going to care for patients who are at least sofek pikuach nefesh. Is there any "shinuy" way of wearing the ID?
Shalom, You are correct in thinking that there is a problem wearing a identification tag in a place with no eruv on Shabbat. See for example Shmirat Shabbat KeHilchatah, chapter 18,25 in the footnote, where he forbids a doctor to go out wearing such a tag. Though there may be room to say that this is considered as some form of jewelry that may be allowed, I did not find any sources that stated as much. Therefore, it seems that the doctors i.d. card which is clipped to their coat is a form of (forbidden) carrying. However, you are correct in assuming that the needs of the ill would allow (and even obligate) the doctor to do everything needed to get to the hospital in order to treat them, including carrying if needed. In general we try to use a "shinui" [- doing things in an unusual manner] if it will not bring about any chance of endangering the sick. So, if using a shinui to carry the id card may slow the doctor down (e.g. if she is suddenly called to the hospital for an emergency) then no shiui should be used. If one can, without any chance of endangering the sick, carry the id with a shinui, then this should be done. A shinui in this case would be to place the card on one's head under a hat. Or to sick it into one's sock etc. Any way that we do not normally carry the id card would be considered as a shinui. Blessings.