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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

 



References:


Iron deficit equation (source): 
[1 ]  Schrier SL, Mentzer WC, Landaw SA. Treatment of anemia due to iron deficiency. UpToDate®. 2010;18(3). http://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: http://www.cosmofer.com/product/dose-calculation/dose-calculator.aspx





Disclaimer

All calculations must be confirmed before use. The authors make no claims of the accuracy of the information contained herein; and these suggested doses are not a substitute for clinical judgement. Neither GlobalRPh Inc. nor any other party involved in the preparation of this program shall be liable for any special, consequential, or exemplary damages resulting in whole or part from any user's use of or reliance upon this material.PLEASE READ THE DISCLAIMER CAREFULLY BEFORE ACCESSING OR USING THIS SITE. BY ACCESSING OR USING THIS SITE, YOU AGREE TO BE BOUND BY THE TERMS AND CONDITIONS SET FORTH IN THE DISCLAIMER.   Read the disclaimer
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