To solve the problem wherein, when calculating a characteristic value of a blood component in the state where blood spot-contacted on a test piece is not diffused sufficiently in a reaction domain on the test piece, a wrong characteristic value is calculated, in a medical diagnosis apparatus.

In the medical diagnosis apparatus having a spot contact detection means for detecting a blood quantity spot-contacted on the test piece, a light source for irradiating the blood on the reaction domain on the test piece with excitation light, a photodetection means for detecting fluorescence emitted from the excitation light and acquiring it as a measured value of a fluorescence quantity, and an operation processing means for calculating the characteristic value of the blood component from the acquired measured value of the fluorescence quantity, a fluorescence value just after spot contact of the blood is compared with a fluorescence value after elapse of a prescribed time after performing spot contact, while monitoring a spot-contact quantity of the blood, and it is determined whether the blood is diffused sufficiently over the reaction domain on the test piece or not based on the comparison result.