Taking Temperature on Shabbos

Ask the Rov: To visit a person in the hospital, a non-Jewish employee measures my temperature with a “gun.” Is this allowed on Shabbos?

By Rabbi Chaim Hillel Raskin – Rov of Anash in Petach Tikvah

Chazal prohibited any form of measuring on Shabbos or Yom Tov (see issue 361), precluding the use of even a non-electric thermometer.¹ Measuring for health needs, or for a mitzva, is permitted, and one may measure fever with a non-electric thermometer.²

Regarding the use of electricity itself on Shabbos – independent of other possible melachos such as turning on lights or writing – there is dispute whether closing a circuit constitutes the melacha d’oraisa of boneh (building) or is prohibited mid’rabanan due to molid (birthing a new energy). Yet, the majority of contemporary poskim hold that it is d’rabanan.³

If an electric thermometer is d’rabanan, then having a non-Jew use it would be a shevus d’shevus, a double d’rabanan, which is allowed for great need or a mitzva purpose. A Jew may not perform the act himself, even a double d’rabanan for the sake of a mitzva.⁴

Is having one’s temperature taken considered taking part in the act?

Shluchan Aruch rules that if a tooth is causing you great pain, you can have a non-Jewish dentist remove it on Shabbos.⁵ Some explain that opening your mouth is only minimal assistance (mesayei’a), and the melacha is still being done entirely by the non-Jew.⁶ Others argue that even such a level of assistance forbidden; it is only permitted in cases that the Jew does not help at all.⁷ The Alter Rebbe follows the first opinion and permits any procedure that the non-Jew could do himself without the Jew preventing him.⁸

Poskim dispute if the exemption of mesayei’a applies by d’oraisa prohibitions as well, and in practice, we are lenient. Therefore, one who is slightly ill and needs a non-Jew to take blood is permitted to stretch out his hand.⁹

Although mesayei’a is permissible on a biblical level, Chazal prohibit it out of concern that one would come to do the melacha on his own. However, they lifted their decree in mitzva and health situations.¹⁰

Examples of qualifying mitzva purposes (for mesayei’a and shevus d’shevus) include to enable the performance of timely mitzvos like shofar, lulav or to transport important components of the Shabbos meal.¹¹

In conclusion , having one’s temperature taken by a non-Jew can be allowed when it is truly needed or for a mitzva purpose.

See Sources (open PDF)