With regard to adding Pyridoxal Phosphate (PALP), which combines with the active sites of AST and ALT, JSCC recommends measuring holoenzymes without adding PALP, reflecting the biological reaction. On the other hand, IFCC recommends the measurement of both holoenzymes and apoenzymes when PALP is added, reflecting the total diverted from the internal organs. It is important which recommendation to follow from a clinical point of view and from the viewpoint of reducing gaps in clinical facilities. Further, it is necessary to consider each isozyme as well as the time difference between apoenzyme and holoenzyme diversion from blood to accurately grasp the pathology and understand the measurement.