30 Iron Deficiency Anemia (IDA)
Michelle To and Valentin Villatoro
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- An image from a peripheral blood smear demonstrating hypochromic and microcytic red blood cells. 50x oil immersion. From MLS Collection, University of Alberta, https://doi.org/10.7939/R3P84499C
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- An image from a peripheral blood smear showing hypochromic, microcytic red blood cells with occasional targets which can beeen in IDA. 60x oil immersion. From MLS Collection, University of Alberta, https://doi.org/10.7939/R3988333G
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- An image from a peripheral blood smear showing hypochromic, microcytic red blood cells. 50x oil immersion. From MLS Collection, University of Alberta, https://doi.org/10.7939/R3KS6JK8F
Cause(s):1,2
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
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Stage 1 (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. |
Stage 2 (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. |
Stage 3 (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
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CBC: RBC Count: Decreased PLT: Variable (increased in chronic bleeding) Hb: Decreased Hct: Decreased MCV, MCH, MCHC: Decreased RDW: Increased |
PBS: Microcytic, hypochromic RBCs Target cells Elliptocytes Teardrop cells Normal WBC morphology |
BM: M:E Ratio: Decreased Erythroid hyperplasia Iron Stores: Absent or severely decreased (not sustainable) |
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Iron Studies: Serum Iron: Decreased Ferritin: Decreased Transferrin: Increased Transferrin Saturation: Decreased TIBC: Increased |
Other Tests: Prussian Blue stain of the BM shows absent or decreased iron Reticulocyte count decreased |
References:
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.
