The Synermed serum iron method is an improvement over most traditional methods in that the detection is in the region of the spectrum where hemoglobin and lipemia have less absorbance than at the wavelength used in traditional methods. The Synermed serum iron is the only automated serum iron method providing reference quality results.
When Is a Serum Iron Really a Serum Iron? A Follow-up Study on the Status of Iron Measurements in Serum. Clinical Chemistry 42, No. 1, 1996 pp 109-111 Norbert W. Tietz, et al.
The [Synermed] method showed good correlation with the ICSH method for specimens with ferritin values 1200 µg/L, the ICSH method showed a positive bias for most values.”
“The ICSH method is subject to interference by ferritin when present in concentrations >1200 µg/L. This observation casts doubt on the suitability of the ICSH method as a reference method for the measurement of serum iron ....”
“Thus, we renew our call for a new Reference Method for measuring serum iron that meets today’s need for accuracy and precision.”
“the accuracy of the Synermed ... method ... is acceptable for use in the clinical laboratory.”
Serum iron is transported in the ferric oxidation state while bound to transferrin. In the Synermed Serum Iron reagent system, the ferric ion is dissociated from transferrin at an acid pH in the presence of ascorbic acid which reduces the ferric ion to ferrous ion. The ferrous ion then reacts with the chromogen Ferene® to form a blue chromophore. The absorbance of the blue iron-dye complex is proportional to serum iron concentration and is read spectrophotometrically at 600 nm.
Transferrin_2Fe+3 -> transferrin + 2Fe+3 -> 2Fe+2 + dehydroascorbate
Fe+2 + Ferene -> Fe+2_Ferene complex