The most accurate way to determine if there is a fever is to use a thermometer to measure it. Because some patients may have conscious hot flashes and fever symptoms, but the temperature monitoring is normal because of some subjective feelings that affect the patient’s judgment, using a thermometer is the most intuitive and reliable way to check. In daily life, infrared thermometers such as frontal thermometers and ear thermometers are more commonly used for temperature monitoring, and this measurement method is relatively easy to obtain the patient’s temperature data in a short time, but the measurement value may have a small deviation. In addition, more commonly used is the use of mercury thermometer to measure the patient’s axillary temperature, this method is longer than the forehead and ear thermometer measurement time, but the measured data is more accurate, and is often used in the clinic, when the body temperature exceeds 37.0 ℃ is fever.