Protein-bound Iodine, Total Iodine, and Butanol-extractable Iodine by Partial Automation.

0 VER the past several years, the measurement of protein-bound iodine (PBT) and butanol-extractable iodine (BET) has become quite popular in evaluating thyroid function. So great has the demand been for these determinations that some laboratories are performing hundreds of the assays per day. In view of these facts, it becomes obvious that automation should be utilized as much as possible to offset the shortage of trained personnel. Since all of these procedures involve the determination of organic iodine bound to protein, some type of digestion is necessary to convert the iodine into its inorganic form, which may be done by either wet ashing or dry ashing. Wet ashing involves digestion with a strong acid, while the dry-ash technic makes use of a muffle furnace and an alkali medium. Attempts are being made to carry out digestion by automation, but without too much success. Consequently, we have not resorted to automation for the purposes of digestion.