What is the management plan for anemia with low Red Blood Cell (RBC) count, low Mean Corpuscular Hemoglobin Concentration (MCHC), high Mean Platelet Volume (MPV), and elevated Red Cell Distribution Width (RDW)?

Management of Anemia with Low RBC, Low MCHC, High MPV, and Elevated RDW

This laboratory pattern strongly suggests iron deficiency anemia, and you must immediately confirm with serum ferritin (<30 μg/L diagnostic, <100 μg/L if inflammation present) and initiate comprehensive gastrointestinal evaluation to identify the source of blood loss, as this presentation in adults warrants investigation for malignancy. 1, 2

Understanding This Laboratory Pattern

The combination of findings points toward iron deficiency:

• Low MCHC indicates reduced hemoglobin concentration within red cells, characteristic of iron deficiency 3
• Elevated RDW reflects heterogeneous red cell populations with varying sizes as iron stores become depleted—this is a specific early indicator of iron deficiency 2, 3
• Low RBC count with anemia confirms inadequate red cell production 1
• High MPV may indicate reactive thrombocytosis or platelet activation, though this is less specific for the diagnosis 3

The elevated RDW is particularly important because it can be the first indicator of iron deficiency before frank microcytosis develops, and may represent early-stage deficiency or combined deficiency states 1, 2

Immediate Diagnostic Workup

Essential Iron Studies

• Serum ferritin: <30 μg/L confirms iron deficiency in the absence of inflammation; <100 μg/L suggests iron deficiency when inflammation is present 2
• Transferrin saturation: <30% supports iron deficiency diagnosis 1, 2
• C-reactive protein (CRP): Mandatory to interpret ferritin correctly, as inflammation elevates ferritin and can mask true iron deficiency 2

Serum ferritin is the most powerful test for iron deficiency and should guide your diagnostic approach 1

Additional Laboratory Tests

• Complete blood count with differential to evaluate other cell lines and confirm the pattern 4
• Reticulocyte count to assess bone marrow response 4
• Peripheral blood smear to evaluate for schistocytes, hemolysis, or other morphologic abnormalities 1

Mandatory Gastrointestinal Investigation

All adult men and post-menopausal women with confirmed iron deficiency require complete gastrointestinal evaluation regardless of symptom presence, as asymptomatic colonic and gastric carcinoma commonly present with iron deficiency anemia. 1, 2

Upper Gastrointestinal Evaluation

• Upper endoscopy with small bowel biopsies: 30-50% will have an upper GI source identified 1, 2
• Small bowel biopsies are mandatory during endoscopy, as 2-3% of patients have celiac disease 1, 2

Lower Gastrointestinal Evaluation

• Colonoscopy or CT colonography: Required even if upper GI source is found, as dual pathology occurs in approximately 10% of patients 2
• Barium enema is an alternative if colonoscopy cannot be performed 1

Critical Investigation Principles

• Document use of NSAIDs, aspirin, and anticoagulants, but do not defer investigation based on medication use 1
• Dietary history should be obtained, but borderline deficient diets should not be presumed as the sole cause—full GI investigation remains required 1
• The absence of GI symptoms does not correlate with investigation findings and should not deter complete evaluation 1

Treatment Approach

Iron Supplementation

• Initiate oral iron supplementation once iron deficiency is confirmed by ferritin testing (or intravenous if malabsorption or intolerance present) 2, 4
• Continue iron for 3-6 months after hemoglobin normalizes to replete iron stores 2
• Monitor response with complete blood count after 4-6 weeks of treatment 4

Treating Underlying Causes

• Treatment of the underlying cause will cure the anemia, making identification of the source critical 1
• Address any identified GI pathology (malignancy, inflammatory bowel disease, celiac disease, angiodysplasia) 1
• Even when no cause is detected, the long-term outlook is good with iron supplementation 1

Critical Pitfalls to Avoid

• Never assume dietary deficiency alone without complete GI evaluation—this can delay diagnosis of malignancy 1, 2
• Avoid empiric iron therapy without confirming iron deficiency with ferritin, as this can cause harm in conditions like thalassemia and delays proper diagnosis 2
• Do not stop investigation after finding one source of bleeding—dual pathology is common 2
• Never interpret ferritin in isolation—always obtain CRP to assess for inflammation that may falsely elevate ferritin levels 2, 4
• If anemia persists despite appropriate treatment or transfusion dependence develops, escalate to further GI investigation or hematology consultation 4