To the Editor.
—The key to Dixon and Laszlo's article "Utilization of Clinical Chemistry Services by Medical House Staff" in the Archives (134:1064-1067, 1974) is their statement that "it remains to be determined by laboratory services whether ultimate cost reductions would warrant the initial costs of instituting selective determinations."At my institution, I am confident that not only the initial costs, but the final costs would be higher, with the use of a selective system. It is frequently not appreciated just how cheap automated chemistry tests can be, especially if hospitals share equipment. Our charge for a single enzyme test is $11, but for the full 12, the charge is only $12. It is always cheaper to do the 12 tests than to do any two by hand. The charges reflect actual costs and are not arbitrary.This implies to me that the house officer's usage of the laboratory was