A portable device for performing coagulation tests on a patient's blood. Blood is first drawn from a patient using a lancet. The blood is then supplied to a disposable cuvette placed within the testing device. The blood is drawn into multiple conduits within the cuvette. Each of the conduits contains a dried or lyophilized activation reagent that is rehydrated by the blood. The blood in each of the conduits is then reciprocally moved across a restricted region until a predetermined degree of coagulation occurs. Since the coagulation time is being monitored in multiple conduits, a representation coagulation time for a given sample can be determined. In at least one of the conduits a normalizing control agent is present. The normalizing control agent counteracts any effects of anticoagulants present in the blood sample, thereby allowing the blood sample to have generally normal coagulation characteristics. The normalized blood is tested simultaneously with the untreated blood to provide a reference value against which the functionality of the test system and the quality of the sample can be judged.