Comparison of plasma ferritin concentration with the ratio of plasma transferrin receptor to ferritin in estimating body iron stores: results of 4 intervention trials

• Published in: The American journal of clinical nutrition Vol. 87; no. 6; pp. 1892 - 1898
• Main Authors: Yang, Zhenyu, Dewey, Kathryn G, Lönnerdal, Bo, Hernell, Olle, Chaparro, Camila, Adu-Afarwuah, Seth, McLean, Erin D, Cohen, Roberta J, Domellöf, Magnus, Allen, Lindsay H, Brown, Kenneth H
• Format: Journal Article
• Language: English
• Published: Bethesda, MD American Society for Nutrition 01.06.2008; American Society for Clinical Nutrition; American Society for Clinical Nutrition, Inc
• Subjects: Adolescent; Adult; Biological and medical sciences; Biomarkers; Biomarkers - metabolism; blood; blood plasma; C-Reactive Protein; C-Reactive Protein - metabolism; Child; Clinical Trials as Topic; Comparative analysis; cost effectiveness; deficiency; Dietary minerals; Feeding. Feeding behavior; Female; ferritin; Ferritins; Ferritins - metabolism; Fundamental and applied biological sciences. Psychology; Humans; Infant; infants; Iron; Iron - metabolism; Iron Deficiencies; iron deficiency anemia; metabolism; Multicenter Studies as Topic; nutrient reserves; Nutrition; nutrition assessment; nutritional intervention; nutritional status; Plasma; Pregnancy; pregnant women; Proteins; Randomized Controlled Trials as Topic; receptors; Receptors, Transferrin; Receptors, Transferrin - blood; school children; transferrin; Vertebrates: anatomy and physiology, studies on body, several organs or systems; Human; Transferrin; Ferritin; Iron; Ratio; Concentration; Comparative study; Blood plasma; Biological receptor
• ISSN: 0002-9165; 1938-3207; 1938-3207
• DOI: 10.1093/ajcn/87.6.1892

BACKGROUND: Efforts to develop global programs for the control of iron deficiency require simple, low-cost, and accurate indicators of iron status. OBJECTIVE: We aimed to compare estimates of body iron (BI) stores, as calculated from either plasma ferritin concentration alone (BI-ferritin) or the ratio of plasma transferrin receptor (TfR) to ferritin (BI-TfR/ferritin). DESIGN: Data were analyzed from 4 previously completed, randomized intervention trials that enrolled infants, schoolchildren, or pregnant women (total n = 1189, after excluding subjects with elevated C-reactive protein). RESULTS: The correlation coefficients between BI-ferritin and BI-TfR/ferritin were >0.95 for all studies. The kappa index ranged from 0.5 to 1.0. All of the sensitivities of BI-ferritin for identifying persons with low iron stores (defined as BI-TfR/ferritin < 0 mg/kg body wt) were >0.90. All of the specificities were >0.90 except the study of pregnant women (specificity = 0.66). The effect sizes of iron intervention trials were significantly greater for change in iron reserves estimated by BI-TfR/ferritin than by BI-ferritin in 2 studies with larger effect sizes (1.11 compared with 1.00 and 1.56 compared with 1.44, respectively; P < 0.05) and 1 study with medium effect size (0.70 compared with 0.57; P < 0.05). However, there were no significant differences between estimates of these effect sizes for 1 study with a medium effect size and 1 study with a smaller effect size (0.78 compared with 0.83 and 0.37 compared with 0.35, respectively; P > 0.2). CONCLUSION: Plasma ferritin concentration alone provides a good approximation of total BI reserves, as estimated by BI-TfR/ferritin, on the basis of high correlation, sensitivity, and specificity among nonpregnant persons with unelevated C-reactive protein.