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Urinary Ferritin as a Noninvasive Means of Assessing Iron Status in Young Children
Najma A Moumin1, Nina D'Vaz2, Courtney Kidd3
1Women and Kids Theme, South Australian Health and Medical Research Institute, Adelaide, South Australia, Australia; Discipline of Pediatrics, Faculty of Health and Medical Sciences, Adelaide Medical School, The University of Adelaide, Adelaide, South Australia, Australia.
Insights
Urinary ferritin shows promise as a noninvasive method to screen for iron deficiency (ID) in young children. This urine test can help exclude ID in healthy children, reducing the need for blood draws.
Area of Science:
- Pediatric Nutrition
- Biomarker Discovery
- Clinical Diagnostics
Background:
- Iron deficiency (ID) is the most common nutritional deficiency in young children.
- Serum ferritin is the gold standard biomarker for iron status but requires blood collection, which is difficult for children.
- A noninvasive method for assessing iron status in children is needed.
Purpose of the Study:
- To assess the correlation between urinary and serum ferritin concentrations in young children.
- To evaluate if correcting urinary ferritin for creatinine and specific gravity improves this correlation.
- To establish a urinary ferritin cut-off point for predicting iron deficiency.
Main Methods:
- A validation study involving 142 three-year-old children from the ORIGINS project in Perth, Western Australia.
- Paired serum and urine samples were collected.
- Sensitivity, specificity, and predictive values were calculated for urinary ferritin in identifying ID.
Main Results:
- Urine ferritin, corrected for creatinine, showed a moderate correlation with serum ferritin (r = 0.53).
- The biomarker demonstrated good performance in predicting ID (AUC: 0.85).
- A cut-off of <2.28 ng/mg creatinine for urine ferritin was 86% sensitive and 77% specific for ID, with a 97% negative predictive value.
Conclusions:
- Urinary ferritin exhibits good diagnostic performance for iron deficiency.
- This noninvasive biomarker may serve as a valuable screening tool to rule out ID in healthy young children.
- Further research in diverse populations is recommended.
Background:
Iron deficiency (ID) is the most common nutritional deficiency affecting young children. Serum ferritin concentration is the preferred biomarker for measuring iron status because it reflects iron stores; however, blood collection can be distressing for young children and can be logistically difficult. A noninvasive means to measure iron status would be attractive to either diagnose or screen for ID in young children.
Objectives:
This study aimed to determine the correlation between urinary and serum ferritin concentrations in young children; to determine whether correcting urinary ferritin for creatinine and specific gravity improves the correlation; and to determine a urine ferritin cut point to predict ID.
Methods:
Validation study was conducted using paired serum and urine collected from 3-y-old children (n = 142) participating in a longitudinal birth cohort study: the ORIGINS project in Perth, Western Australia. We calculated the sensitivity, specificity, positive, and negative predictive values of urinary ferritin amount in identifying those with ID at the clinical cut point used by the World Health Organization (serum ferritin concentration of <12 ng/mL).
Results:
Urine ferritin, corrected for creatinine, correlated moderately with serum ferritin [r = 0.53 (0.40-0.64)] and performed well in predicting those with ID (area under the curve: 0.85; 95% confidence interval: 0.75, 0.94). Urine ferritin <2.28 ng/mg creatinine was sensitive (86%) and specific (77%) in predicting ID and had a high negative predictive value of 97%; however, the positive predictive value was low (40%) owing to the low prevalence of ID in the sample (16%).
Conclusions:
Urine ferritin shows good diagnostic performance for ID. This noninvasive biomarker maybe a useful screening tool to exclude ID in healthy young children; however, further research is needed in other populations.
