A test strip for testing two or more analytes in a fluid sample concurrently, the test strip comprising: a first planar substrate with a plurality of coplanar electrodes on a first planar surface and a second planar substrate with a plurality of coplanar electrodes (10A, 10B) on a second planar surface, the first planar substrate and the second planar substrate being arranged such that the first surface of the first planar substrate opposes the second planar surface of the second planar substrate; a planar intermediate layer disposed in between the first surface of the first planar substrate and the second planar surface of the second planar substrate, said intermediate layer made from a dielectric or insulating material which isolates coplanar electrodes and coplanar electrodes from one another; wherein said planar intermediate layer defines a fluid flow path which allows fluid to flow from the inlet to the outlet of the test strip; the first planar surface of the first planar substrate having individual sensing areas, said individual sensing areas being associated with respective, individual coplanar electrodes; the second planar surface of the second planar substrate having additional individual sensing areas associated with some of the respective individual coplanar electrodes; and wherein chemicals and/or reagents are directly applied on the coplanar electrode (4, 10A) and define the individual sensing areas; each of the one or more, up to all, of the individual coplanar electrodes of the second planar substrate not associated with a sensing area being electrically connected to a respective coplanar electrode via a conductive element; and wherein the conductive elements extend between the first surface of the first planar substrate and the second surface of the second planar substrate, without passing through the first planar substrate or the second planar substrate and each conductive element electrically connects an electrode with an electrode, and wherein the area of the first planar surface of the first planar substrate and the intermediate layer are both smaller than the area of the second planar surface of the second planar substrate, thereby leaving a portion of the area of the second planar surface uncovered by the first planar substrate as well as intermediate layer, said exposed portion containing a portion of electrodes referred as coplanar electrical contacts, which may be in use interfaced with an associated medical instrument. a first planar substrate with a plurality of coplanar electrodes on a first planar surface and a second planar substrate with a plurality of coplanar electrodes (10A, 10B) on a second planar surface, the first planar substrate and the second planar substrate being arranged such that the first surface of the first planar substrate opposes the second planar surface of the second planar substrate; a planar intermediate layer disposed in between the first surface of the first planar substrate and the second planar surface of the second planar substrate, said intermediate layer made from a dielectric or insulating material which isolates coplanar electrodes and coplanar electrodes from one another; wherein said planar intermediate layer defines a fluid flow path which allows fluid to flow from the inlet to the outlet of the test strip; the first planar surface of the first planar substrate having individual sensing areas, said individual sensing areas being associated with respective, individual coplanar electrodes; the second planar surface of the second planar substrate having additional individual sensing areas associated with some of the respective individual coplanar electrodes; and wherein chemicals and/or reagents are directly applied on the coplanar electrode (4, 10A) and define the individual sensing areas; each of the one or more, up to all, of the individual coplanar electrodes of the second planar substrate not associated with a sensing area being electrically connected to a respective coplanar electrode via a conductive element; and wherein the conductive elements extend between the first surface of the first planar substrate and the second surface of the second planar substrate, without passing through the first planar substrate or the second planar substrate and each conductive element electrically connects an electrode with an electrode, and wherein the area of the first planar surface of the first planar substrate and the intermediate layer are both smaller than the area of the second planar surface of the second planar substrate, thereby leaving a portion of the area of the second planar surface uncovered by the first planar substrate as well as intermediate layer, said exposed portion containing a portion of electrodes referred as coplanar electrical contacts, which may be in use interfaced with an associated medical instrument.