In the scientific papers about EPO I read RBC volume (mL) expansion. What is it? The volume of a single cell or the volume expansion (=that is the increase of the number of cells) caused by the EPO?

Thank you in advance.

EDIT: see fig.1 page 3 please http://s000.tinyupload.com/index.php?file_id=08669957844938542361

  • $\begingroup$ Please provide context in the form of a citation from one of the papers together with a link. Otherwise your question is likely to be voted as off-topic because it is unclear. $\endgroup$
    – David
    Commented Sep 18, 2017 at 18:48
  • $\begingroup$ Hi @David. See fig.1 page 3 please s000.tinyupload.com/index.php?file_id=08669957844938542361 $\endgroup$ Commented Sep 18, 2017 at 19:32
  • $\begingroup$ Fine, by the place for this in your question. Please edit it accordingly. $\endgroup$
    – David
    Commented Sep 18, 2017 at 19:37

1 Answer 1


Red blood cell volume is the percent of blood taken up by red blood cells (also known as the hematocrit), and is expressed as a percentage (so, normally, RBCs should comprise x% of blood by volume.) It says nothing of the size of the red blood cells.

That needs to be done by measuring the mean corpustular volume either by special machine or by looking at a slide of cells. So if the MCV is not mentioned, you can assume that expansion is referring to increased number of RBCs.

Smaller than normal RBC's are called microcytes, larger than normal are called macrocytes.

Recombinant EPO just increases the production of RBCs (and, unfortunately, it has some other effects as well.) It should not affect the size of the final erythrocyte.

  • $\begingroup$ Hi @anongoodnurse. If possible, can you link me some references about the sentence "It should not affect the size of the final erythrocyte." please? My unreliable professor said that EPO causes the increase of the size of RBCs. Thank you for your answer. $\endgroup$ Commented Sep 19, 2017 at 5:27
  • $\begingroup$ @GennaroArguzzi - I appreciate that you would like sources. I actually read a couple of papers about recombinant human EPO and in all the papers, it just discusses RBC volume, which is already defined. In none of the papers does it list RBC indices (that is, cell size, hemoglobin, the number of reticulocytes, etc.) If there's no problem (EPO has been used in dialysis patients for decades now) with the end result for erythrocytes (there are other problems: too many plateletts are produced as well, and a few other things), then it boils down to accepted terminology, as above. $\endgroup$ Commented Sep 19, 2017 at 14:31

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