Method for separating isoanalytes and measuring analytes in fluids

An apparatus for separating isoanalytes and measuring analytes in fluids includes a two-chambered filtration device having a filter positioned parallel to the majority flow of fluids. The apparatus uses continuous flow filtration to separate one component from other fluid components. An alternative apparatus for separating isoanalytes and measuring analytes in fluids includes a reaction chamber which uses intermittent flow filtration with a piston/valve assembly to separate one component from other fluid components. A method for separating isoanalytes and measuring analytes in fluids comprises the steps of: mixing a fluid sample and a precipitating reagent; directing the mixture to a filtration device; adding a color reagent; directing the filtrate to an analyzer; replacing the fluid sample with a wash solution; and replacing the precipitating reagent with a cleaning solution. An alternative method for separating isoanalytes and measuring analytes in fluids comprises the steps of: directing a fluid sample to a reaction chamber; directing a precipitating reagent to the reaction chamber; mixing the fluid sample and the precipitating reagent; applying pressure to the reaction chamber; adding a color reagent to the filtrate; directing the filtrate to an analyzer; and replacing the fluid sample and the precipitating reagent with a cleaning solution.