Anemia Management in CKD Patients

Initial Laboratory Assessment

The National Kidney Foundation recommends a complete blood count with reticulocyte count, iron studies, and assessment for other potential causes of anemia for CKD patients with anemia (low hemoglobin and hematocrit) 1, 2
A complete blood count (CBC) includes hemoglobin, hematocrit, red blood cell indices, white blood cell count, and platelet count to assess bone marrow function 1, 3
Reticulocyte count evaluates bone marrow response to anemia; a low count in CKD patients with adequate iron stores suggests insufficient erythropoietin production or inflammation 3, 4
Iron studies, including serum ferritin and transferrin saturation, reflect tissue iron stores and iron available for erythropoiesis, respectively 1, 3, 4

Absolute iron deficiency is defined as serum ferritin <25 ng/mL in males and <11 ng/mL in females (non-dialysis CKD) 4
Functional iron deficiency is defined as transferrin saturation ≤20% with elevated ferritin levels 4

The American Journal of Kidney Diseases recommends a stool guaiac test for occult blood when iron deficiency is detected 5
Vitamin B12 and folate levels should be checked when macrocytosis is present 1, 5
C-reactive protein should be assessed to evaluate inflammation when ferritin levels are elevated 4
Hemoglobinopathy evaluation should be performed when microcytosis is present but iron studies are normal 1

For hemodialysis patients, blood samples should be obtained before the midweek dialysis session, and predialysis hemoglobin measurements should be used (postdialysis values vary with fluid removal) 4, 6

The National Kidney Foundation recommends an initial complete workup for CKD patients with anemia, followed by routine monitoring at minimum yearly screening for all CKD patients 1, 2
More frequent monitoring is recommended for diabetic CKD patients and during treatment with erythropoiesis-stimulating agents 1, 2

Hemoglobin is preferred over hematocrit for monitoring anemia in CKD patients due to better reproducibility, lower coefficients of variation, and lack of effect from sample storage time or hyperglycemia 3, 5, 7
Ferritin is an acute-phase reactant and may be elevated in inflammation despite iron deficiency, while transferrin saturation may be more reliable than ferritin in the presence of inflammation 4