Oxidant-based radioiodination of "inactive" creatine kinase B protein.

to produce reliable results. This conclusion is based on the study by Obzansky and Lott (2), which involved the Cardiozyme (Dade Div., American Hospital Supply Corp., Miami, FL 33152) immunoinhibition test for CKMB. Two other assays based on similar principles-EskachemTM CK-MB Reagent (SmithKbine Instruments, Inc., Sunnyvale, CA 94086) and A-gent CK-MB (Abbott Labs., North Chicago, IL 60064)-are marketed in the United States. In both of these latter assays the CK measurement system, with altered activators, is appreciably more sensitive than that incorporated in the Dade product. We believe that the use of this more sensitive measurement system demonstrably produces reliable results without the necessity for special photometric equipment. Diagnostic sensitivity and specificity are also enhanced by other changes in the reagent system which decrease and (or) quantitate positive and negative interferences. A description by Gerhardt and Waldenstr#{246}mof this revised and improved assay system has appeared in this journal (3), and is referenced without comment in Lott and Stang’s Table 1 as ref. 27. Although referred to in the table simply as munoinhibition Method,” it is very different from the method receiving similar appellation in the text. Iminunoinhibition assays for CK-MB are now available in diverse enough form that comments about the technical and diagnostic adequacy of one test generation do not necessarily apply to later iterations. Certainly it would be appreciated, for instance, that an assessment of the sensitivity of total CK assays based on the early Tanzer-Gibvarg (creatine substrate) reaction scheme would not lead to the same conclusion as a review of the batter assays based on the Oliver-Rosalki (creatine phosphate substrate) reaction scheme. In a quickly evolving technology such as clinical enzymobogy, precision is commendable not only in the assays themselves, but also in the references to them. The relatively casual reader often needs aid in seeing the recent specifics amongst the older generalities. In the present instance, the only applicable generality is that not all immunoinhibition assays are alike.