Clinical Significance of Reticulocyte Hemoglobin as a Diagnostic Tool for Evaluation of Anemia in Veterans.

Reticulocyte hemoglobin content (CHr), is a reliable marker of iron function, rather than iron stores alone, especially in patients with renal failure. Whether it is as effective in patients with hematologic and oncologic disease is not known. We therefore evaluated the usefulness of CHr for diagnosis of different types of anemia among the Veterans at the CAVHS (Central Arkansas Veteran Healthcare System), Little Rock. We evaluated all patients with anemia seen in the Hematology/Oncology clinic at CAVHS from 7/1/2004 through 6/30/2006. We obtained demographics of patients and laboratory data including CBC, reticulocyte count, CHr, serum iron, total iron binding capacity (TIBC), iron saturation, ferritin, vitamin b12 and folate from the CPRS electronic database. Using STATA program, we analyzed the relation between CHr, RBC indices and other iron storage parameters. A total of 183 patients were evaluated. Patients had mean age 69, ranging from 35 to 98 years. The majority were men with only 9 women. Patients were whites (75%), African Americans (17%), or others (7%). Mean CHr was 32 pg with range from 18.7 to 50.4 pg (normal value 24 to 36 pg). High CHr (>36 pg) was present in 24 patients (13.1 %). High CHr was associated with high MCV in all cases and included patients with vitamin b12 deficiency, myelodysplasia, myelofibrosis, large granular lymphocyte leukemia, chronic lymphocytic leukemia, autoimmune hemolytic anemia, HIV infection on HART as well as those who had received total body irradiation or were taking methotrexate, or azathioprine. Low CHr (<24pg) was present in 8 patients. All of them had low MCV and had iron deficiency anemia, including one with ferritin over 1000ug/ml, presumably high as an acute phase reactant since iron saturation was only 6%. This patient had active head and neck cancer and had received chemotherapy and radiotherapy. CHr did not correlate with other parameters of iron such as ferritin (r=0.14), iron saturation (r=0.57) or TIBC (r= −0.16) in the pooled analysis of all anemias. CHr did correlate well with RBC indices MCV (r=0.86) and MCH (r=0.89) but not so well with MCHC (r= 0.62).

In summary, Reticulocyte hemoglobin content is a good marker of iron function and may be superior to ferritin since it does not change with acute conditions. However it correlates well with MCV and MCH, and therefore does not appear to provide significant independent diagnostic advantage over MCV. Since MCV is readily available and is inexpensive, CHr offers relative little advantage for routine evaluation of anemia.