Table 1.

Benefits and shortcomings of clinical iron measurements

Iron parameter	Benefits	Shortcomings
Hepcidin	Ease of measurement	Diurnal variation28 High (∼49%) within-person variation31,32
%Hypo	Sensitive, reliable marker of functional iron deficiency (when ≥6%)33	Unreliable indicator of short-term changes in iron status
Reticulocyte Hb concentration	Ease of measurement (decreased in both absolute and functional iron deficiency)27	Lack of standardized reference methods across laboratories31 Variations in results because of sample transport and storage31
Serum ferritin	Reliably indicates iron status in noninflammatory conditions (decreased in absolute iron deficiency)27 May be used in combination with low TSAT (normal or elevated in functional iron deficiency)33	Unreliable indicator of iron status in the presence of inflammation12,27
Serum iron	Ease of measurement	Diurnal variation29 High (∼30%) within-person variation31 Further decreased in inflammatory conditions31
Soluble transferrin receptor	Ease of measurement (increased in absolute iron deficiency)27	Lack of standardized reference methods across laboratories31 Affected by inflammation (decreased in functional iron deficiency)27
TIBC	Ease of measurement	Diurnal variation12
TSAT	Ease of measurement (decreased in both absolute and functional iron deficiency)27 May be used in combination with serum ferritin to diagnose functional iron deficiency33	Same as those of its components (serum iron and TIBC)34
Bone marrow examination	Accuracy	Painful, cannot repeat often

%Hypo, percentage of hypochromic red cells; Hb, hemoglobin; TIBC, total iron binding capacity; TSAT, transferrin saturation.