30 Iron Deficiency Anemia (IDA)

Michelle To and Valentin Villatoro


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

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


RBC Count: Decreased

PLT: Variable (increased in chronic bleeding)

Hb: Decreased

Hct: Decreased

MCV, MCH, MCHC: Decreased

RDW: Increased


Microcytic, hypochromic RBCs

Target cells


Teardrop cells

Normal WBC morphology


M:E Ratio: Decreased

Erythroid hyperplasia

Iron Stores: Absent or severely decreased (not sustainable)

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


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.


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Iron Deficiency Anemia (IDA) Copyright © 2019 by Michelle To and Valentin Villatoro is licensed under a Creative Commons Attribution-NonCommercial 4.0 International License, except where otherwise noted.

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