A method and system for testing the functional capability of an analytical instrument uses first and second blind samples. Each blind sample is a test substance with an amount of a parameter to be tested that is unknown to the user. Each blind sample is provided with an identification means with a unique identification. When the blind samples are tested by the user in the instrument being tested, the measurement values obtained and the unique identifications read are compared against predetermined values that are accessible to a test program configured as software on the analytical instrument. By comparison of the measurement values and the predetermined values, the functional capability of the analytical instrument is determined and the result is transmitted to an output unit of the analytical instrument.