Devices, kits, and methods are disclosed for use in detecting a concentration of an analyte of interest in a patient's liquid test sample. The devices, kits, and methods employ the use of one or more solid reagent zones that includes at least one analytical reagent for detection of an analyte of interest. The solid reagent zone(s) also includes at least one dye for determining whether results obtained from the diagnostic assay for the at least one analyte of interest are biased or inaccurate due to a loss of volume of a liquid reagent during the dispensing of the liquid reagent.