Taking the temperature
TAKING THE TEMPERATURE
27. One who is sick with a high temperature of unknown cause is considered to be in the category of a seriously ill patient.
28. One may measure temperature, pulse and blood pressure on the Sabbath. The thermometer may be cleansed with alcohol which is then wiped off with dry cotton-wool. However one may not do so with cotton-wool soaked in alcohol. After use, the thermometer may be shaken down if it is to be used again on the Sabbath. The type of contact thermometer which is blank before use and on which figures can be seen only after it has been in contact with the skin, may not be used on the Sabbath unless the patient is seriously ill or possibly so, and it is not possible otherwise to take his temperature. A digital thermometer may not be used for a non-seriously ill patient.
29. A woman who is measuring her temperature daily in order to ascertain the time of ovulation, may do so also on the Sabbath.
 Shemirat Shabbat Kehilchata 40:2. See Nishmat Avrahm Pt. 4, Orach Chayyim 328:1 (page 59).
 Shemirat Shabbat Kehilchata 328, note 8* in the name of R. Sh.Z. Auerbach.
 Written communication from R. Y.Y. Neuwirth.
 Shemirat Shabbat Kehilchata ibid.