An electrochemical test sensor for detecting the concentration of an analyte in a fluid test sample, the electrochemical test sensor comprising: a base that provides a flow path for the fluid test sample having on its surface only two electrodes, namely a counter electrode and a working electrode in electrical communication with a detector of electrical current, a lid including a concave space defined by a three-dimensional portion that mates with the base to exclusively define a capillary space, the lid having an opening for the introduction of fluid test sample thereto, and a reagent layer including an enzyme that reacts with the analyte, wherein the electrodes have different shapes within the capillary space, characterized by: an area of the working electrode adapted to interact with the analyte in the fluid test sample including a main portion and at least one secondary portion extending therefrom within the capillary space, and the reagent layer being directly located on the surface of the main portion of the working electrode and the at least one secondary portion of the working electrode such that there is no intervening layer between the reagent layer and the working electrode, wherein the main portion is fully exposed in the concave space, and wherein the area of the main portion is substantially larger than the secondary portion exposed to the fluid test sample. a base that provides a flow path for the fluid test sample having on its surface only two electrodes, namely a counter electrode and a working electrode in electrical communication with a detector of electrical current, a lid including a concave space defined by a three-dimensional portion that mates with the base to exclusively define a capillary space, the lid having an opening for the introduction of fluid test sample thereto, and a reagent layer including an enzyme that reacts with the analyte, wherein the electrodes have different shapes within the capillary space, characterized by: an area of the working electrode adapted to interact with the analyte in the fluid test sample including a main portion and at least one secondary portion extending therefrom within the capillary space, and the reagent layer being directly located on the surface of the main portion of the working electrode and the at least one secondary portion of the working electrode such that there is no intervening layer between the reagent layer and the working electrode, wherein the main portion is fully exposed in the concave space, and wherein the area of the main portion is substantially larger than the secondary portion exposed to the fluid test sample. an area of the working electrode adapted to interact with the analyte in the fluid test sample including a main portion and at least one secondary portion extending therefrom within the capillary space, and the reagent layer being directly located on the surface of the main portion of the working electrode and the at least one secondary portion of the working electrode such that there is no intervening layer between the reagent layer and the working electrode, wherein the main portion is fully exposed in the concave space, and wherein the area of the main portion is substantially larger than the secondary portion exposed to the fluid test sample.