The mercury thermometer is a durable medical device, if the frequency of daily use is small and well preserved, no damage, cracking, malfunction and other phenomena, even if it exceeds the shelf life, it can continue to use.
If the use of a long time, the number of times, can lead to the mercury thermometer surface scale is rubbed off, and the thermometer is prone to malfunction, the mercury can not float with the temperature change and other malfunctions, this time the thermometer can not be achieved to measure the temperature of the estimated value of the role of the temperature, in this case, it is not recommended to re-use.