The amount of iron lost and the amount needed to replace it following a known blood loss can be calculated from the estimated volume of blood loss.


(1) normochromic, normocytic red blood cells contain 1 mg of elemental iron for each 1 mL of red blood cells.

(2) hemoglobin is approximately 0.34% iron by weight


mg of iron lost =

= (volume of blood loss in mL) * (hematocrit in percent) / 100


mg of iron lost =

= (hemoglobin in g/dL) * (mL of blood loss) / 100 * 0.0034 * 1000



• mL blood loss divided by 100 converts the blood loss to deciliters.

• The 1000 is for conversion from grams to milligrams.

• The amount of iron in plasma is much lower than that associated with hemoglobin.


If iron dextran is used for replacement (iron content 50 mg/mL):


volume of iron dextran to administer in mL =

= (mg of iron to replace) / 50

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