| abstract |
An analytical element for determining analytes in aqueous liquids, such as biological fluids, has therein a spread control zone comprising a polymeric material that is naturally soluble in water. The polymer dissolves upon contact with the aqueous sample, thereby increasing the viscosity of the aqueous sample such that the spread of the aqueous sample in the element is reduced. The element is used by contacting, in the presence of an indicator composition for providing a detectable change in response to the analyte, a finite area of the element with the aqueous sample and determining the presence or amount of the analyte as a function of the detectable change in the indicator composition. |