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.