Modern iron ligands useful for the measurement of serum iron
Zak, B.; Baginski, E.S.; Epstein, E.
Annals of Clinical and Laboratory Science 10(4): 276-289
1980
ISSN/ISBN: 0091-7370 PMID: 7004329 Document Number: 166540
A concise review of iron ligands presently used for the determination of serum Fe and its ancillary unsaturated Fe binding capacity is presented. The review includes a discussion of critical areas involved in Fe determinations affecting the use of these ligands such as serum blanking, standardization and the effect of blanking on standardizations, method complexity, molar absorptivities, potential interferences, choice of reducing agent and procedural sensitivity according to selected dilution conditions along with sample and physiological variables as exemplified by diurnal variations and posture effects; volume exclusion effects as a function of serum treatment; high lipid concentration as a volume effect; therapeutic interferences, hemolysis, irrelevant absorption and jaundice; and the use of molar absorptivity as a quality control standardization check. From several possible choices, one sensitive ligand, 2,4-bis(5,6-diphenyl-1,2,4-triazin-3-yl) pyridine tetrasulfonate, is selected which is suitable for contemporary filtrate methodology and needs. A procedure is described detailing its use for the determination of serum Fe in the routine mode. The determination of Fe-binding capacity is included for the sake of completeness of the procedure. The ligand selected here can be substituted for less sensitive ligands in other direct determinations, manual or robotized, or in continuous flow spectrophotometry for either direct or dialysate technology because the compound reacts in a similar manner to ligands presently acceptable in the field of serum Fe and Fe-binding capacity quantification.