Test		Finding	Possible etiology
Complete blood count
	RBC indices	MCV < 80 μm3 per cell (80 fL)	Iron deficiency anemia
			Anemia of chronic disease
		MCV > 100 μm3 per cell (100 fL)	Vitamin B12 deficiency; folate deficiency
		MCV normal	Renal, liver and thyroid diseases as well as those above
	WBC and platelet counts	Abnormal	Primary marrow production problem
Peripheral smear		Burr cells	Chronic renal failure
		Spherocytes, fragments	Hemolytic diseases
		Dysplastic changes	Myelodysplasia
	Reticulocyte count	< 1%	Inadequate production in presence of anemia
		≥1%	Increased production but unclear whether it is of appropriate magnitude; reticulocyte index helpful for clarification
	Reticulocyte index*	≥2	Reticulocyte release appropriate for anemia
		< 2	Inadequate response to anemia