Abstract: A digital thermometer (10) includes a temperature measuring device (13) for measuring temperature of an examinee. A microprocessor (12) is coupled to the temperature measuring device for processing a sequence of temperature samples measured during a unitary measuring interval and is responsive to the measured temperature samples or a function thereof for determining at least one health property other than temperature of the examinee or for predicting a change in at least one health property of the examinee such as an onset of an abnormal health condition. According to one embodiment, volatility of the temperature-time characteristic is used to indicate whether the examinee is healthy or not, even when no fever is registered. ‘Volatility’ is a measure of the extent to which temperature samples fluctuate with time, such as the number of temperature rises and falls during the sampling period.