This evaluation of two CPBAs confirmed that the presence of apo-HC can interfere with the analysis. However, when proteins
are inactivated and denaturized by heat in the presence of dithiothreitol and potassium cyanide, interferences due to HC or nonspecific protein activities are not observed. Both, the SimulTRAC and Centaur use basic conditions to liberate B12 from HC without heat treatment.