Introduction: Chronic Kidney Disease (CKD) is a condition of progressive loss of kidney function. Some cases are followed by Iron Deficiency Anemia (IDA). For the diagnosis of IDA, serum ferritin and serum transferrin receptor (sTfR) are the common used parameters to determine iron status. As these two parameters might be affected by inflammation or infection, an alternative assessment tool is important. Reticulocyte, the immature form of erythrocyte, is then targeted for the measurement. By evaluating Reticulocyte Hb equivalent (RET-He) and reticulocyte Hb content (CHr), it will give benefit to the early detection of iron-deficient state. Hereafter, CHr is used as the most common parameter for iron state assesment. However, in Indonesia, RET-He is a much more common. Thus, in this study, we evaluate the comparison between RET-He and CHr in the assesment of iron states in CKD patients.
Methods: A number of 125 CKD patients aged from 18 to 64 years old were enrolled in this study. RET-He and CHr levels were determined using Hematology Analyzer XN 1000 (Sysmex, Kobe, Japan) and Advia 120 Hematology (Bayer diagnostics, NY, USA), consecutively. The RET-He was then further compared to CHr for for their mean difference (bias) and Limits of Agreement (LoA) using Bland-Altman method.
Result: After performing measurements of RET-He and CHr in CKD patients, we found that bias and LoA between both parameters were -2.13 pg and -5,99 to 1,73 pg, respectively. The bias value showed that RET-He had tendency for higher measurement of iron status than CHr. Furthermore, the LoA value indicated unsatisfactory agreement.
Conclusion: We demonstrated that RET-He and CHr have discrepancy level in CKD patients. Thus, RET-He cannot be used as substitute for CHr in the measurement of iron status. Further studies are needed to determine the reference value for each parameters.
Keywords: RET-He, CHr, IDA, CKD