Diagnostic testing device and diagnostic testing method

A diagnostic testing device for immunochromatography, in which a liquid sample that potentially contains an analyte is flowed in an analyte detection area via a labeling-substance-containing area of a test strip, and an interpretation of negative or positive is made on the basis of a coloration state exhibited by the analyte detection area, the diagnostic testing device comprising:

• a measuring part configured to obtain, once or more, data on a coloration index constituting an index associated with a coloration state for a range including at least part of the analyte detection area;
• and
• a processing part configured to deliver interpretation on the basis of the coloration index data, wherein
• the processing part is configured to deliver a negative interpretation when the coloration state of the analyte detection area is in a negative state in data of the coloration index obtained at least one time with a maximum set to N times (wherein N is greater than 1), and deliver a positive interpretation when the coloration state of the analyte detection area is in a positive state in data of the coloration index of all of the N times.