Chronic Blood Loss (heavy menstruation, intermittent GI bleeding, etc.)
Increased Need (periods of rapid growth, pregnancy)
Inadequate intake (diet)
Impaired absorption (malabsorption)
Notes: When there is not enough iron to meet the requirements of the body, iron stores begin to deplete, and IDA occurs. Development of IDA occurs over a period of time.1-4
IDA development is said to occur in three stages:3
(Storage Iron Depletion):
– Normal RBC maturation
– Decline in storage iron (decreased ferritin, decreased iron stores in the bone marrow)
– No other evidence of anemia development.
(Transport Iron Depletion):
– Decreased serum iron and ferritin
– Transferrin and TIBC levels increase
– Absent iron stores in the bone marrow
– Evidence of anemia is not as apparent.
(Functional Iron Depletion- IDA):
– Anemia is evident
– PBS shows microcytic, hypochromic RBCs
– RBC development is affected
– Same iron study results as stage 2
– Hb is decreased
– Hepcidin is decreased
– Erythropoietin is increased
Laboratory Features of Iron Deficiency Anemia (At Stage 3):1-4
RBC Count: Decreased
PLT: Variable (increased in chronic bleeding)
MCV, MCH, MCHC: Decreased
Microcytic, hypochromic RBCs
Normal WBC morphology
M:E Ratio: Decreased
Iron Stores: Absent or severely decreased (not sustainable)
Serum Iron: Decreased
Transferrin Saturation: Decreased
Prussian Blue stain of the BM shows absent or decreased iron
Reticulocyte count decreased
1. McKenzie SB. Anemias of disordered iron metabolism and heme synthesis. In: Clinical laboratory hematology. 3rd ed. New Jersey: Pearson; 2015. p. 198-230.
2. Miller JL. Iron deficiency anemia: A common and curable disease. Cold Spring Harb Perspect Med [Internet]. 2013 Jul 1 [cited 2018 Jun 28];3(7):10.1101/cshperspect.a011866 a011866. Available from: http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3685880/
3. Doig K. Disorders of iron kinetics and heme metabolism. In: Rodak’s hematology clinical applications and principles. 5th ed. St. Louis, Missouri: Saunders; 2015. p. 297-313.
4. Finnegan K. Iron metabolism and hypochromic anemias. In: Clinical hematology and fundamentals of hemostasis. 5th ed. Philadelphia: F.A. Davis Company; 2009. p. 117-37.