insolubilized serum protein adsorbent , for example bovine serum albumin , of small particle size is an excellent adsorbent for adsorbable components in a biological fluid such as serum . macroaggregated and polymerized albumin are particularly suited as adsorbents for unbound thyroid hormone in serum and can be used in diagnostic kits for determining total t 4 and for t 3 uptake .