The goal of this work was to optimize the existing test methods for measuring bulk copper and nickel impurities in the heavily doped p-type silicon wafers and to assess their sensitivity, recovery rate, and correlation. Three test methods were studied; low-temperature out-diffusion, polysilicon ultratrace profiling, and wafer digestion. The bulk copper and nickel recovery rates of low-temperature out-diffusion were improved by one order of magnitude in the concentration around 2 x 10(12) atoms/cm(3). Among the three test methods, polysilicon ultratrace profiling and wafer digestion were found to be most sensitive and the method detection limit of 5 x 10(11) atoms/cm(3) or better was achieved after optimization. The optimized wafer digestion and polysilicon ultraprofiling also correlated well across six laboratories with a bias less than +/- 50% for both bulk copper and nickel. (C) 2006 The Electrochemical Society.