CAP TODAY Pathology/Laboratory Medicine/Laboratory Management
Editor: Deborah Sesok-Pizzini, MD, MBA, professor, Department of Clinical Pathology and Laboratory Medicine, Perelman School of Medicine, University of Pennsylvania, Philadelphia, and chief, Division of Transfusion Medicine, Children’s Hospital of Philadelphia.
Use of hemoglobin content of reticulocytes to evaluate anemia in cancer patients
Studies of age of transfused blood relative to mortality in select cardiovascular patients
Use of hemoglobin content of reticulocytes to evaluate anemia in cancer patients
Evaluating iron-deficiency anemia in patients with cancer is difficult. Malignancy is frequently associated with anemia of chronic disease. However, it is important to distinguish iron-deficiency anemia due to inadequate iron stores from anemia of chronic disease due to decreased iron availability with abundant stores. Advanced reticulocyte indices, such as the cellular hemoglobin content of reticulocytes, named CHr and RET-He, are reportable parameters on newer automated hematology analyzers. These indices are known to correlate with iron-deficient erythropoiesis in certain populations and may help monitor patients’ responses to iron-replacement therapy. However, there is little data on the utility of using RET-He in evaluating complex anemias in malignancy. The authors conducted a study in which they examined the use of RET-He to rule out iron deficiency in an unselected cancer patient population. Patients who had concurrent laboratory test requests for CBC and serum iron studies were entered in the study. Using a threshold of 32 pg/cell, the results showed that RET-He ruled out iron deficiency with a negative predictive value of 98.5 and 100 percent in the study cohort and in a subpopulation of patients with low reticulocyte counts. However, the specificity was low, most likely due to the high selected RET-He threshold relative to the reference range. Additional studies are needed to determine how well RET-He can distinguish iron-deficient or iron-restricted hematopoiesis from bone marrow suppression. The data support the use of RET-He to rapidly rule out iron-deficient erythropoiesis and to reduce the amount of unnecessary iron studies in a cancer patient population.
Peerschke EIB, Pessin MS, Maslak P. Using the hemoglobin content of reticulocytes (RET-He) to evaluate anemia in patients with cancer. Am J Clin Pathol. 2014;142:506–512.
Correspondence: Dr. Ellinor I. B. Peerschke at peersche@mskcc.org
Studies of age of transfused blood relative to mortality in select cardiovascular patients
Several observational studies have investigated the association between duration of blood storage before transfusion—referred to as “age of blood”—and mortality. These studies have produced conflicting results. In a previous study, the authors reported an association between exposure to older blood and in-hospital mortality among transfused cardiovascular patients admitted to the hospital between 2002 and 2006. They conducted a more recent study on an expanded cohort of patients admitted from 2002 to 2011 with the intent of replicating the previous analysis to reaffirm the conclusions from the earlier study. For the latter study, Cox regression models were fitted to assess the effect of RBC storage duration on risk of in-hospital mortality in cardiovascular patients. A total of 9,669 patients received 46,868 RBCs. The median number of units transfused was three, and the median age of the RBCs was 17 days. Interestingly, the previous progressive increase in risk of in-hospital mortality with transfusion of older blood was not observed in the larger cohort. The authors noted that although these results did not demonstrate an association of age of blood with in-hospital mortality, randomized control trials alone can reliably indicate if an association exists. They suggested that the previous findings may simply be a false-positive error or that the method of whole blood processing may have affected the quality of the stored RBCs, impacting patient outcomes.
Heddle NM, Eikelboom J, Liu Y, et al. Exploratory studies on the age of transfused blood and in-hospital mortality in patients with cardiovascular diagnoses. Transfusion. 2015;55:364–372.
Correspondence: Nancy M. Heddle at heddlen@mcmaster.ca