A testing unit to test a liquid sample applied on a measurement surface in an indicator section on a test piece by using a brightness distribution. The testing unit comprises an irradiation part that irradiates the measurement surface with light; an imaging part that obtains images of the measurement surface; a generating part that generates a determination index based on the imaging data; and a determination part that executes determination on a measurement item, using the determination index. The determination index is based on a brightness of the measurement surface when the measurement surface does not include a specular reflection region. The determination index is based on a brightness of a remnant region of the measurement surface excluding the specular reflection region when it is determined that the measurement surface includes a specular reflection region.

A method of producing a reagent tape, that includes a base tape layer and a series of consecutive and separate reagent pads of a reagent, is provided for use in a milk sampling device. The milk sampling device is arranged to supply a droplet of a milk sample onto one of the reagent pads on the tape in order to produce a response in the reagent to detect a presence or concentration of a substance in the milk sample. The method includes providing the base tape layer of the reagent tape, applying onto the base tape layer a continuous layer of the reagent, dividing the supplied continuous reagent layer into separate reagent pads by providing a hydrophobic barrier line between said pads. This may be done by laser ablating thin lines of reagent material, or by providing additional hydrophobic material into the layer. Thus, a simple and fast way of providing a tape with pads is obtained, in which a narrow spacing between pads is possible. A tape made by the method, and a milking device with a sampling device with such a tape are disclosed.