**2.5 Human body**

In relation to iodine determinations, in clinical practice the most frequent analytical samples include urine, serum, blood, and a variety of tissues. Therefore, some examples of research studies related to iodine determinations in the mentioned matrices are presented below. The bioavailability of organic iodine, especially associated with macromolecules, is low (Hou et al., 2009), whereas I and IO3 - have high bioavailability. According to recent estimates, KI is almost completely absorbed in humans (96.4%) (U.S. Food and Drug Administration [FDA], 2009).
