Serum transferrin receptor in children and adolescents with inflammatory bowel disease

Iron studies are difficult to interpret in patients with chronic inflammato ry states such as inflammatory bowel disease (IBD). Serum transferrin recep tor (TfR) has been reported to be a reliable tool for the diagnosis of iron deficiency in adults. Our aim was to evaluate the role of serum TfR in dia gnosing iron deficiency in children and adolescents with IBD. A total of 63 consecutive patients with IBD, aged 9 to 22 years (median 15 years), were tested for serum haemoglobin level, mean corpuscular volume (MCV), and seru m iron, transferrin, ferritin and serum TfR levels. Those found to be anaem ic were compared with seven age-matched subjects with iron deficiency anaem ia (IDA) and 24 age-matched children without signs of anaemia or inflammati on. Of the 63 patients with IBD, 26 had anaemia. Based on ferritin levels a nd MCV indices, anaemia was classified as IDA in 11 patients and as anaemia of chronic disease (ACD) in 15 patients. Mean serum TfR level in normal co ntrols was 3.5 mg/l (range 1.2-8.2 mg/l). Mean (+/- SD) serum TfR levels we re significantly lower in the IBD patients with ACD (5.3 +/- 2.3 mg/l) than in the IBD patients with IDA (8.2 +/- 3.1 mg/l) (P < 0.05). Serum TfR leve ls above 5 mg/l identified 10/11 IBD patients with IDA. The calculated TfR/ ferritin ratio was 84 (range 17-367) for controls and 133 (range 6.4-1840) for IBD patients. A cut-off level of 350 (91% sensitivity, 100% specificity , 100% positive predictive value, 98% negative predictive value) was establ ished for the diagnosis of IDA in IBD. Conclusion The results suggest that serum transferrin receptor is a useful parameter for the diagnosis of iron deficiency in inflammatory bowel diseas e, in particular, the transferrin receptor/ferritin ratio with a cut-off le vel greater than or equal to 350.