We showed that the content of reticulocyte hemoglobin (CHr) is a reliable measure of iron status with regard to erythrocytopoiesis in chronic dialysis status. The mean CHr level was 32.3 +/- 2.2 pg in dialysis patients and CHr was significantly correlated with the conventional parameters of iron deficiency. We aimed to utilize the measurement of CHr levels to monitor iron status in clinical practice. We measured CHr, iron parameters, and the intrinsic EPO concentration in non-dialysis CRF patients to clarify the alterations in CHr levels that occur as renal anemia progresses. CRF patients who visited our out-patient clinic (n = 189) were included in the study. Iron deficiency was defined by the transferrin saturation and ferritin levels. Conventional red blood cell parameters and CHr levels were measured using an ADVIA120 autoanalyzer (Bayer Medical, USA). The mean CHr value of the non-dialysis patients (creatinine clearance less than 70 ml/min) was 32.7 pg, which did not differ significantly from that of the dialysis patients. Significant correlations were found between CHr and TSAT (r = 0.032, p < 0.0177), unlike the correlation with intrinsic EPO levels. Overall, 11% of the patients were diagnosed as having iron deficiency. There was a positive correlation between CHr and serum creatinine levels. Non-dialysis CRF patients treated with rHuEPO at the dose of 24,000 U/month showed different CHr levels compared with other patients (less than 24,000 U/month). It is possible that rHuEPO treatment in non-dialysis patients affects iron dynamics. In conclusion, CHr is an easily measurable and reliable marker of iron status in non-dialysis CRF patients. Moreover, the CHr level was also sensitive to iron alternations in non-dialysis CRF patients under rHuEPO treatment. Accordingly, if long-acting EPO is available for non-dialysis CRF patients, the CHr value is likely to be indicative of the need for iron supplementation.