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Calculation of the Total Iron Deficit – Alternative equation

Calculation of Parenteral Iron Dose  (Iron Deficit)

Equations:
Hemoglobin iron deficit (mg) = weight (kg)  x (14 - Hgb) x (2.145) 1
Note: Hbg (current hemoglobin level) units: (g/dL)

Alternatively: Volume of product required (mL) = [weight (kg) x (14 - Hgb) x (2.145)] / C
Where C= concentration of elemental iron (mg/ml) in the product being used:
Iron dextran: 50 mg/mL. Iron sucrose: 20 mg/mL.  Ferric gluconate: 12.5 mg/mL

Note (alternative equations): 
[1 ] The Iron dextran package insert lists the following equation:
Dose (mL) = 0.0442 (Desired Hb - Observed Hb) x LBW + (0.26 x LBW)
Iron dextran calculator can be found here.

[2 ] The current package insert for CosmoFer® lists the following equation:
Total iron deficit = Body weight [kg] x (Target Hb – Actual Hb) [g/l] x 2.4 + Iron stores [mg]
500 mg iron for iron stores is recommended if the body weight is above 35 kg.
A calculator using this equation can be found here.
 Patient Weight:  
Current Hemoglobin level:    g/dL
Target (desired) Hemoglobin level:   g/dL

Background:
Iron deficit - equation derivation1 :
Assumptions:
   -Blood volume = 65 mL/kg
   -Hgb conc target =14.0 g/dL
   -Deficits in body stores are ignored.

Intermediate calculations:
  -Blood volume (dL) =  [65 (mL/kg) x body weight (kg)] / 100 (mL/dL)
  -Hgb deficit (g/dL) = 14.0 - patient hgb conc.
  -Hgb deficit (grams) = Hgb deficit (g/dL) x blood volume (dL)
  -Iron deficit (mg) = Hgb deficit (grams) x 3.3 (mg Fe/g Hgb) 
         [Note: 3.3 x 0.65 = 2.145]
  -Volume of parenteral iron product req'd (mL) = [Iron deficit (mg)] / C(mg/mL)

Final calculations:
  -Hgb iron deficit (mg) = weight (kg) x (14 - Hgb) x (2.145)
  -Volume of product required (mL) = [weight (kg)x (14 - Hgb) x (2.145)] / C
        Where C= concentration of elemental iron (mg/ml) in the product being used:
         Iron dextran: 50 mg/mL. Iron sucrose: 20 mg/mL.  Ferric gluconate: 12.5 mg/mL

RBC

References:

Iron deficit equation (source): 
[1 ]  Schrier SL, Mentzer WC, Landaw SA. Treatment of anemia due to iron deficiency. UpToDate®. 2010;18(3). https://www.uptodate.com/ (Requires subscription). Accessed: 4/12/2011.

Alternative equation:
Total iron deficit = Body weight [kg] x (Target Hb – Actual Hb) [g/l] x 2.4 + Iron stores [mg]
500 mg iron for iron stores is recommended if the body weight is above 35 kg.

[2 ] CosmoFer® package insert and  product website: https://www.cosmofer.com/product/dose-calculation/dose-calculator.aspx
Calculation of the Total Iron Deficit – Alternative equation

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