From the Guidelines
In anemia due to kidney disease, lab results typically show low hemoglobin and hematocrit levels, low red blood cell count, normal or slightly low mean corpuscular volume (MCV), low reticulocyte count, low serum erythropoietin levels, elevated creatinine and blood urea nitrogen (BUN) levels, and low or normal iron studies (serum iron, ferritin, transferrin saturation) 1. These lab findings reflect the reduced production of erythropoietin by the diseased kidneys, leading to decreased red blood cell production. The anemia is usually normocytic and normochromic. Iron studies may be normal or low due to reduced iron utilization. Elevated creatinine and BUN indicate impaired kidney function. To diagnose and manage this condition, a complete blood count (CBC), comprehensive metabolic panel, and iron studies should be ordered. Erythropoietin levels can also be measured but are not always necessary for diagnosis. Treatment typically involves erythropoiesis-stimulating agents (ESAs) like epoetin alfa or darbepoetin alfa, along with iron supplementation if needed. Some key points to consider in the diagnosis and management of anemia in CKD include:
- The primary cause of anemia in patients with CKD is insufficient production of erythropoietin (EPO) by the diseased kidneys 1.
- Iron deficiency is a common contributing factor to anemia in CKD patients, and iron supplementation is often necessary to achieve adequate erythropoiesis 1.
- The use of ESAs has been shown to improve quality of life and reduce the need for blood transfusions in CKD patients with anemia 1.
- The target hemoglobin level for ESA therapy in CKD patients is a subject of ongoing debate, with some studies suggesting that higher target levels may be associated with improved quality of life but increased risk of adverse events 1.
- Iron status should be assessed using serum ferritin, transferrin saturation, and mean corpuscular volume (MCV), with consideration of other markers such as percent hypochromic red blood cells (PHRBC) and content of hemoglobin in red blood cells (CHr) if available 1.
From the FDA Drug Label
The FDA drug label does not answer the question.
From the Research
Laboratory Findings in Anemia Associated with CKD
The laboratory findings in anemia associated with Chronic Kidney Disease (CKD) include:
- Decreased hemoglobin levels, with a diagnosis of anemia made when hemoglobin is <12 g/dL in men or postmenopausal women, or <11 g/dL in premenopausal women 2
- Decreased erythropoietin production, which can be assessed through laboratory tests 3, 4
- Iron deficiency, which can be absolute or functional, and is a common cause of resistance to erythropoietin therapy 3, 4, 5, 6
- Increased hepcidin levels, which can limit iron absorption from the gut 3, 4
- Shortened red cell lifespan and enhanced blood loss, which can contribute to anemia 3
- Inflammation, which can increase hepcidin levels and contribute to anemia 3, 4
Diagnostic Tests
Diagnostic tests for anemia in CKD include:
- Estimation of glomerular filtration rate (GFR) to assess kidney function 2
- Hemoglobin tests to diagnose anemia 2
- Iron studies, including transferrin saturation and ferritin levels, to assess iron status 2, 5, 6
- Erythropoietin levels to assess erythropoietin production 3, 4
Treatment-Related Laboratory Findings
Treatment-related laboratory findings in anemia associated with CKD include:
- Response to erythropoietin-stimulating agents (ESAs), which can be assessed through hemoglobin levels and iron studies 3, 4, 2
- Response to iron supplementation, which can be assessed through iron studies and hemoglobin levels 3, 4, 5, 6
- Potential for iron deficiency or overload, which can be assessed through iron studies 5, 6