Second, the test standards
⒈ ⒈ infrared thermometer for medical use GB T 21417.1-2008
⒉EU standard: EN 12470-5-2003
3 U.S. standard: ASTM E 1965-1998 R2003
The U.S. standard is the most stringent, mainly reflected in the environmental humidity.
The European Union's is a little looser, only the requirement of environmental humidity is a little narrower than the U.S. standard.
But the Chinese national standard is the loosest.
From these standards, infrared ear thermometers are not necessarily accurate even if they pass China's national standards!
Because the Chinese national standard only specifies verification ((23 ± 2) °C/(50 ± 20) %.) This ambient temperature point and this very narrow range of ambient humidity.
But the Chinese national standard gives the ambient temperature for ear thermometer use as 16 °C ~ 35 °C. This means that in addition to ((23 ± 2 °C) / (50 ± 20) %. This means that the 16 °C ~ 35 °C range specified in the standard has not been validated, except for (23 ± 2) °C.
This is exactly where the Chinese national standard should be revised.
Started to be accurate, then not allowed. The main reason for this is that some imported brands such as Taiwan's brand Ikel and most domestic ear thermometer manufacturers in order to cater to the Chinese public's consumerism, the design of the ear thermometer without the ear cushion, the probe will inevitably be dirty after a long time, affecting its accuracy. This is also the reason why major brands such as Braun do not make this design.
Lastly, I would like to answer the question about the temperature comparison, the normal body temperature of each part of the human body is different, so the armpit temperature measured by the mercury thermometer and the ear temperature measured by the ear thermometer to do the comparison is not right. Normal body temperature varies with the location of the measurement, the specific differences can refer to the following table.