Normocytic Anemia Workup
Initial Evaluation
- The American College of Physicians recommends starting the workup for normocytic anemia with a reticulocyte count to distinguish between decreased RBC production and increased RBC destruction/loss, followed by targeted testing based on this result 1, 2
- Initial laboratory assessment should include a complete blood count (CBC) with red cell indices, reticulocyte count, peripheral blood smear review, serum ferritin, transferrin saturation, and C-reactive protein (CRP) or inflammatory markers 2, 3, 6
Algorithmic Approach
- A low or normal reticulocyte index (RI <2.0) indicates decreased RBC production, and further testing should include iron studies, renal function, inflammatory markers, and additional testing if necessary 1, 2, 3, 4
- Elevated reticulocyte index (RI >2.0) indicates increased RBC destruction or loss, and immediate evaluation for hemolysis and hemorrhage is necessary 1, 2, 3, 4
Hemolysis Workup
- Lactate dehydrogenase (LDH) should be elevated, haptoglobin decreased, and indirect (unconjugated) bilirubin elevated in cases of hemolysis 3, 8
- Direct antiglobulin test (Coombs test) should be performed to identify immune-mediated hemolysis, and peripheral smear examination should be done to look for schistocytes, spherocytes, or other abnormal RBC morphology 2, 3
Hemorrhage Evaluation
- Stool guaiac test for occult gastrointestinal bleeding should be performed, and clinical signs of bleeding (melena, hematochezia, menorrhagia, hematuria) should be assessed 1, 2, 3, 8
Critical Pitfalls to Avoid
- Ferritin levels can be falsely elevated in the presence of inflammation, and transferrin saturation should be used to evaluate iron deficiency 3, 4, 7
- Combined deficiencies can coexist and neutralize each other, resulting in a falsely normal MCV, and an elevated RDW suggests this scenario 3, 4, 6
- Peripheral smear review should not be delayed, as visual examination is critical and may reveal findings not apparent from automated indices alone 1, 2