A hand-held test meter includes a strip port connector to receive a test strip. A signal-measurement circuit applies a periodic voltage signal across a sample applied to the strip and detects a resulting current signal. The circuit provides data of the current signal at a digitizing frequency and a selected phase with respect to the voltage signal. A processor records one or more value(s) of the data and then alters the selected phase. Value(s) are thus recorded at each of a plurality of phases. The processor determines a phase difference of the current signal with respect to the voltage signal using the respective sets of value(s). A method for employing a test meter and a test strip is also disclosed, and includes measuring a respective plurality of points for each of a plurality of different measurement phases and determining a phase difference of a fluid sample therefrom.