Reticulocyte hemoglobin content (CHr) can be measured on autoanalyzers and when low is associated with a higher blood transfusion rate in critically ill patients.
Determination of the CHr provides an early measure of functional iron deficiency because reticulocytes are the earliest erythrocytes released into blood and circulate for only one to two days.
Spanish scientist examined the blood of 62 intensive care unit (ICU) patients for CHr as a predictor of transfusion requirements. These patients with functional iron deficiency may be at higher risk for developing anemia that would require blood transfusions. Reticulated hemoglobin was measured using the reticulocyte channel of the Sysmex XE-2100 Automated Hematology Analyzer (Sysmex Corporation; Kobe, Japan; www.sysmex.co.jp). The threshold for a low CHr was set at 29 pg/L
Twenty-three patients (37%) presented with low CHr on ICU admission and tended to be sicker and more likely to have sepsis than those with normal CHr. They were also more prone to complications, particularly acute renal failure and nosocomial infections. The overall transfusion rate was 22.6%, being higher in low-CHr patients than in normal-CHr patients. Median ICU stay was also longer in patients with low CHr.
The scientists concluded that the data suggests that a single parameter obtained at ICU admission, CHr, can clearly separate patients with a higher likelihood of needing a transfusion from those with a lower likelihood. In addition, these “functionally” iron deficient patients might conceivably be a suitable target for preemptive treatment options such as intravenous iron therapy. Low CHr may also be a good predictor of the response to intravenous iron in chronic hemodialysis patients. The study was carried out at the Hospital Sant Joan de Deu-Fundació Althaia, (Manresa, Spain; www.althaia.cat) and the detailed results were published in the May 2010 issue of Anesthesiology.
Image: The XE-2100 automated hematology analyzer (Photo courtesy of Sysmex).