Reticulocyte hemoglobin and hypochromic erythrocytes in the study of erythropoiesis in patients with inflammatory bowel disease.

Anemia due to lack of iron (absolute or functional deficiency) is a common complication of inflammatory bowel disease (IBD). We investigated the potential utility of reticulocyte hemoglobin content (Ret-He) and percentage of hypochromic red cells (Hypo-He) in the assessment of erythropoiesis. We recruited 123 anemic outpatients with IBD. Biochemical tests for iron deficiency were carried out. Full blood counts were performed on a XN 20 system (Sysmex Diagnostics). Differences among groups were studied using analysis of variance and post-hoc tests, considering p < .05 to be significant. Receiver operating characteristic analysis was used to assess the diagnostic performance of Ret-He and Hypo-He for detecting iron-deficient erythropoiesis. The gold standard used for diagnosing iron deficiency was soluble transferrin receptor (sTfR), with a cut-off of >52 nmol/L. Overall, 60 patients had iron deficiency anemia (IDA), 27 anemia of chronic disease (ACD) and 36 mixed ACD + IDA. Ret-He showed the best performance, with an area under curve (AUC) of 0.858 (95% CI 0.816-0.952), considering a cut-off of 30.0 pg, sensitivity of 76.8% and specificity of 99.8% (vs. AUC 0.727 [95% CI 0.624-0.814], considering a cut-off of 4.0%, sensitivity 72.0% and specificity 72.5% for Hypo-He). Ret-He and Hypo-He can be used to assess iron supply for erythropoiesis in patients with IBD, to evaluate long-term (Hypo-He) and short-term (Ret-He) periods.