Erythrocyte Index

February 10, 2011

By Michael Ford, MD

Faculty Peer Reviewed

“Blood Count”

2.65 x 10[13] # of erythrocytes in circulation, assuming Hematocrit 45%[1]
120 Lifespan in days of an erythrocyte[2]
2.5 million # of new erythrocytes produced each second to replace dying cells
5.3 million # of erythrocytes per microliter of blood†,*
4,000 – 11,000 # leukocytes per microliter of blood[2]
150,000 – 400,000 # platelets per microliter of blood[2]
15.9 Grams of Hemoglobin A per deciliter of blood
64,400 Molecular mass in grams of Hemoglobin A (protein tetramer)[3]
1.48 x 1020 Molecules of Hemoglobin A per deciliter of blood
280 million Molecules of Hemoglobin per erythrocyte
30.4 x 10-12 Mass in grams of Hemoglobin per erythrocyte[4]
> 95 % dry mass of an erythrocyte that is composed of Hemoglobin[5]
4 Iron atoms per molecule of Hemoglobin A[3]
1,120,000,000 Iron atoms per erythrocyte
2.9 x 1022 Iron atoms bound to Hemoglobin A in 5 liters blood
55.8 Molecular mass in grams of elemental Iron[6]
2.65 Total grams of Iron bound to Hemoglobin in blood
65 % of total body Iron that is Hemoglobin-bound[2]
11 – 15 Total daily Iron in milligrams in a Western diet[7],*
0.9  – 1.3 Milligrams of Iron absorbed daily via dietary sources[7],*
5.6 – 8.1 Years that would be required for dietary absorption of Hemoglobin-bound Iron

Dr. Ford is a 3rd year resident at NYU School of Medicine

Peer reviewed by Susan Talbot, MD, Attending Physician, Dept. of Medicine Division of hematology/oncology, NYU Langone Medical Center

Image courtesy of Wikimedia Commons.


1.  All of the above calculations use Human indices and assume a 5 liter total blood volume, average erythrocyte volume of 85 fL (85 x 10-15 L), and Hematocrit 45%.

2.  Hoffbrand, Pettit, and Moss, Haematology, 4th Ed.  Blackwell Science LTD, Oxford UK, 2001.

3.  Steinberg MH, “Structure and function of normal human hemoglobins” in UpToDate Online Version 18.1 (last section edit February 2010).

4.  Williams’ Hematology, 6th Ed, Beutler E, Lichtman MA, Coller BS, et al (Eds), McGraw-Hill, New York NY, 2001.

5.  Wintrobe MM, Clinical Hematology, 4th Ed. Lea & Febiger, Philadelphia PA, 1956.

6.  “The periodic table of the elements”. International Union of Pure and Applied Chemistry.

7.  Adamson JW, “Ion deficiency and other hypoprolifterative anemias” in Harrison’s Principles of Internal Medicine, 16th Ed, Kasper DL, Braunwald E, et al (Eds), McGraw-Hill Professional, New York, NY, 2004.

† Calculated using numbers referenced on this page.

* There is variation between men and women.  For example, women have 4-5 million erythrocytes per microliter, while men have 5-6 million.  American men consume more Iron than American women, about 15 mg per day compared with 11 mg, but they absorb a smaller percentage (6% compared with 12%).

One comment on “Erythrocyte Index

  • Avatar of Terry Giorno
    Terry Giorno on

    Would you happen to know the relative weight and volume of each cell type in 1 microliter of blood?

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