Modification in Ramsay's method for correct measurement of total iron-binding capacity.

Lack of satisfactory literature evidence and experiences with results of quality control assessment trials in The Netherlands prompted reconsideration of the determination of total iron-binding capacity (TIBC) in human and control sera. It was found that for a correct determination of serum TIBC the Fe(III)-saturating reagent must be able to correct an abnormally high serum pH due to a subnormal CO2 content of the sample. Such low CO2 contents are frequently found in reconstituted quality control sera. Detailed studies on combinations of mixtures of serum with varying pH and Fe(III)-saturating solutions with increasing amounts of added acid revealed a linear equation of the minimum amount of acid needed in relation to the original serum pH.