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Comparison of plasma ferritin concentration versus the ratio of plasma transferrin receptor/ferritin to estimate total body iron stores: results of four intervention trials
Author(s) -
Yang Z,
Dewey K G,
Lonnerdal B L,
Hernell O,
Chaparro C M,
AduAfarwuah S,
McLean E R,
Cohen R J,
Domellof M,
Allen L H,
Brown K H
Publication year - 2007
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.21.5.a164-c
Subject(s) - ferritin , transferrin , zoology , medicine , transferrin receptor , gastroenterology , iron status , soluble transferrin receptor , chemistry , immunology , endocrinology , iron deficiency , anemia , biology
We compared estimates of body Fe stores (BIS) calculated from plasma ferritin concentration alone (BISF) or the ratio of transferrin receptor/ferritin (BISR) for infants, school children or pregnant women enrolled in previously completed intervention trials (total N=1346). The 165 subjects (12.3%) with elevated CRP (>10 mg/L) were excluded from analysis. The correlation coefficients between BISF and BISR were >0.93 for all 4 studies both before and after intervention. The Kappa index ranged from 0.5–1.0, indicating moderate to high agreement between BISF and BISR. All the sensitivities of BISF for identifying individuals with low Fe stores (defined as BISR<0 mg/kg BW) were greater than 0.9, except for the youngest age group (4 mo old infants) (sensitivity=0.67) and all specificities were greater than 0.9, except for pregnant women (specificity=0.66). The effect sizes of Fe intervention trials were significantly greater for change in Fe reserves estimated by BISR than by BISF for studies with larger effect sizes (0.92 vs 0.79, 1.42 vs 1.28, P<0.001). However, there were no differences between estimates for studies with smaller effect sizes (0.83 vs 0.78, 0.35 vs 0.37, P>0.2). Plasma ferritin concentration alone provides a good approximation of total body Fe reserves, as estimated by ratio of transferrin receptor/ferritin, based on high correlation, sensitivity and specificity among individuals with non‐elevated CRP.