The Usefulness of the Serum Transferrin Receptor to Serum Ferritin Ratio for Discriminating between Iron Deficiency Anemia and Anemia of Inflammation

BACKGROUND: The incidence of iron deficiency anaemia in infants, which is caused by the increased iron demand for rapid growth during this period, is reported to range from 10 to 40%. This age group also suffers from a number of acute illnesses (urinary tract infection, pneumonia and other viral illness). The aim of this study was to evaluate the usefulness of soluble transferrin receptor (sTfR) values and the different methods of calculating the sTfR and serum ferritin (SF) ratio for differentiating anemia of inflammation (AI) from iron deficiency anemia (IDA) or a mixture of these two types of anemia.

METHODS: 173 infants among all the infants who visited Gyeongsang National University Hospital from 2000 to 2006 were enrolled in this study. The hemoglobin (Hb), SF and sTfR values were checked and the infants were divided into the Al subgroup (Hb <11g/dL and SF > 50microgram/L), the IDA subgroup (Hb <11g/dL and SF < 12microgram/L), the normal group (Hb > or =11g/dL and SF > or =12microgram/L), and the unclassified anemia (UCA) group (Hb <11g/dL and SF 12~50microgram/L).

RESULTS: The mean sTfR and sTfR/Log SF values in the AI group were 3.89 and 10.6microgram/mL, respectively (P<0.01). These values in the IDA group were 1.9 and 36.11, respectively (P<0.01). The mean Log (sTfR/SF) was statistically significant between all the subgroups (1.35 in AI, 3.29 in IDA, 1.76 in Nor and 2.35 in UCA). All the infants in the IDA group had a Log (sTfR/SF) value >2.55 whereas all the infants classified in AI group had a Log (sTfR/SF) value <2.55.

CONCLUSION: The Log (sTfR/SF) value is a useful criterion for discriminating between AI and IDA.