Which statement about iron methods is true?

The correct statement regarding iron methods is that colorimetric methods measure the binding of Fe2+ to a ligand such as ferrozine. This method is widely used in clinical laboratories for determining iron levels in serum because it allows for the formation of a colored complex when ferrous iron (Fe2+) binds to ferrozine. The intensity of the color produced is proportional to the concentration of iron in the sample, facilitating a straightforward quantitative analysis using spectrophotometric techniques.

In contrast, other methods mentioned are not as straightforward in their representations. While atomic absorption spectroscopy is a sensitive technique for measuring the concentration of various metals, including iron, it is not universally regarded as the method of choice for serum iron assessments due to factors like cost, sample preparation, and the need for specialized equipment. Additionally, serum iron measurement by potentiometry is not a standard practice, as potentiometric methods are typically applied in different contexts, such as measuring concentrations of ions in solution rather than metals like iron. Lastly, while interference from hemoglobin (Hgb) is a valid concern in iron assays, correcting for it directly with a serum blank is not a standard approach, as it does not effectively isolate the specific interference in these assessments.