The Importance of Serum Transferrin Receptor and TfR-F Index in the Diagnosis of Iron Deficiency Accompanied by Acute and Chronic Infections

This study evaluated the diagnostic superiority of serum transferrin receptor (sTfR) measurement to other laboratory tests performed for the determination of iron deficiency caused by chronic disease (CD). Study group consisted of 114 anemic patients allocated into 3 groups at the pediatrics clinic of Ankara University, Faculty of Medicine and 32 healthy pediatric subjects as the control group. sTfR value ranged between 11.00 nmol/L and 26.20 nmol/L for the control group. However, it was 61.29 ± 39.33 nmol/L in iron deficiency anemia (IDEA) group, consisting of 51 patients. While there was a significant positive correlation between sTfR and Hb, MCV, serum iron, ferritin levels, there was a significantly inverse correlation between sTfR with RDW in the IDEA group. Mean sTfR value was found 47.05 ± 28.07 nmol/L in the acute infection (AI) group consisting of 22 patients, 39.31 ± 26.16 nmol/L in the CD group with 41 patients. Statistically significant difference was found between sTfR of IDEA group and sTfR of the AI group, though accompanied by iron deficiency. These findings showed that sTfR levels were suppressed. That all hematologic parameters including ferritin and sTfR of all patients in the CD group were heterogenous and revealed both normal and abnormal values was noteworthy. To determine the existence of accompanying iron deficiency, sTfR values above 28.10 nmol/L were chosen. It was concluded that the diagnosis of these patients was not possible without sTfR measurement. TfR-F index (sTfR/log ferritin) was found 97.72 ± 108.81 in the IDEA group, 52.16 ± 66.25 in the AI group, and 24.36 ± 43.00 in the CD group (p< 0.001). TfR-F index values of the chronic disease anemia group (ACD) and the iron deficiency anemia group accompanied by chronic disease (COMBI) were compared. The difference between these two groups was statistically significant (p< 0.001). Thus, TfR-F index proved useful in evaluating the changes of iron metabolism and reducing iron necessities in patients.