Method of determining whether there is a test sample supply

A method for determining whether a testing specimen is supplied to a testing system, including a reaction tank in which the testing specimen reacts;

• a light source for emitting testing light into the reaction tank from one side of the reaction tank;
• and a photoelectric sensor that is placed on the side of the reaction tank opposite to the light source for receiving the testing light traveled through the reaction tank and that converts the received testing light into an electrical signal,
• the method comprising:
• setting an amount of the testing specimen to be added into the reaction tank so that a level of the testing specimen is above a light path of the testing light;
• determining whether the testing specimen is supplied based on the presence or absence of change of the electrical signal output from the photoelectric sensor;
• and
• increasing an intensity of the testing light emitted from the light source in cases where the electrical signal from the photoelectric sensor barely changes or does not change, and then determining whether the testing specimen is supplied based on the presence or absence of change of the electrical signal output from the photoelectric sensor.