From the Guidelines
The patient's laboratory results indicate a need for further evaluation to determine the cause of the elevated erythropoietin level, which may be due to tissue hypoxia, anemia, or an erythropoietin-producing tumor, as suggested by the elevated erythropoietin level of 21.7 mIU/mL 1. The reticulocyte hemoglobin panel could not be performed due to specimen stability issues, but iron studies show normal values with an iron level of 58 ug/dL, TIBC of 293 ug/dL, UIBC of 235 ug/dL, and iron saturation of 20%, all within reference ranges. Haptoglobin is normal at 243 mg/dL, indicating no significant hemolysis, and ferritin is 151 ng/mL, showing adequate iron stores. Transferrin is 247 mg/dL, which appears to be within normal limits. Some key points to consider in the evaluation of anemia include:
- The morphologic approach, which characterizes anemia based on the mean corpuscular volume (MCV) 1
- The kinetic approach, which focuses on the underlying mechanism of anemia, distinguishing among the production, destruction, and loss of RBCs 1
- The reticulocyte count, which provides an indication of the RBC production capacity by the bone marrow 1
- Iron status, which is an important part of the initial evaluation of anemia in patients with CKD, as iron deficiency is a common contributor to anemia in CKD 1 Further clinical correlation and possibly additional testing, such as a stool guaiac test for occult blood or a bone marrow biopsy, would be needed to determine the cause of the elevated erythropoietin and to guide management, as suggested by the clinical practice guidelines for evaluation of anemia 1. It is also important to consider the patient's symptoms and medical history in the evaluation and management of anemia, as well as the potential need for iron therapy, as guided by results of iron status tests together with hemoglobin levels, ESA dose, and patient status 1.
From the Research
Reticulocyte Hemoglobin Equivalent (RET-He) and Iron Status
- The study 2 found a significant positive correlation between RET-He and serum iron (SI), transferrin saturation (TSAT), and ferritin in chronic kidney disease (CKD) patients.
- Another study 3 evaluated the concordance between the reticulocyte hemoglobin content (CHr) and RET-He in dialysis patients, and found that RET-He is a sensitive indicator of iron-deficiency anemia.
- The study 4 found that RET-He and the percentage of hypochromic red cells (%Hypo-He) provide information about individual cell characteristics, and can be used to evaluate erythropoiesis and iron status.
Erythropoietin and Iron Availability
- The study 5 found that erythropoietin levels are positively associated with the components of the metabolic syndrome, except cholesterol, and that even mild renal failure blunts erythropoietin production.
- Another study 6 found that hepcidin-25 is positively associated with IL-6, and negatively with total iron binding capacity, intrinsic factor antibody, and transferrin, while RET-He is associated positively with Hb, serum ferritin, serum iron, transferrin saturation, and negatively with serum creatinine, reticulocyte, IL-6, STfR.
Laboratory Test Results
- The provided laboratory test results show that the patient's iron bind.capacity (TIBC) is 293 ug/dL, which is within the reference range of 250-450 ug/dL.
- The patient's UIBC is 235 ug/dL, which is within the reference range of 111-343 ug/dL.
- The patient's iron level is 58 ug/dL, which is within the reference range of 38-169 ug/dL.
- The patient's iron saturation is 20%, which is within the reference range of 15-55%.
- The patient's erythropoietin level is 21.7 mIU/mL, which is above the reference range of 2.6-18.5 mIU/mL.
- The patient's haptoglobin level is 243 mg/dL, which is within the reference range of 38-329 mg/dL.
- The patient's ferritin level is 151 ng/mL, which is within the reference range of 30-400 ng/mL.
- The patient's transferrin level is 247 mg/dL, which is not provided with a reference range.