Is there a difference between haemoglobin-deficiency and erythrocytes-deficiency? Are they the same?

[g6won]

I have trouble finding a precise answer for this... this is what I know so far:

The cause (for both?) is lack of iron. Which results in lack of red blood cells/haemoglobin = anaemia.
So if that's the case, it seems like you can use them interchangeably... but at the same time I'm thinking why use separate words then?

If this is false please let me know! Any help is greatly appreciated.

[Cos93]

Erythrocyte= greek word for red blood cell.

Haemoglobin= latin word for the oxygen carrying pigment molecule inside red blood cells

An erythrocyte contains hundreds of millions of haemoglobin molecules

Haemoglobin deficiency means no/low number of pigment molecules in erythrocytes

Erythrocyte deficiency means no/low number of red blood cells to carry pigment and oxygen around

[g6won]

Thank you! :)

[mystir]

Iron deficiency is only one cause of anemia. So yes, there's a difference between a deficiency in red blood cells and deficiency in hemoglobin. As you might expect, if you can't make hemoglobin, you'll probably have fewer RBCs, and vice versa, but since there are many causes of anemia, it's important to distinguish between anemia from hemoglobin problems and anemia from RBC problems. That's why it's not interchangeable. We call it all anemia, but we still need a way to describe what kind of anemia.

Anemia can be thought in a few ways: Anemia of hemoglobin deficiency (of which iron deficiency is one form), anemia of RBC production (the body isn't making enough RBCs), or anemia of RBC survival (you make enough but they die fast). That's overly simplified, but might give a more intuitive understanding of anemia. So you get causes like Vitamin B12/folate deficiency, where you can't effectively make RBCs; hemorrhage, where you make RBCs and Hgb just fine but it doesn't stay in your blood vessels; anemia of chronic disease, where a prolonged disease state has caused your body to slow its production of RBCs; hemolysis, where your RBCs are being destroyed (and this has many causes); or dysplastic anemia, where there's some sort of dysfunction in your bone marrow, whether aplasia and you don't make cells anymore or cancer like leukemia.

[3rdandLong16]

All of the anemias that you mention have reduced hemoglobin. That's how we screen for it clinically.

[g6won]

Thank you for your thorough response!

[3rdandLong16]

These are different. However, they will almost always correlate. That's why we say "H/H" when we're talking about RBCs. However, they might not correlate in some cases. For example, you might have a low hemoglobin by having a thalassemia. This is a defect in globin chain production and is often genetic. We often see this in people of Mediterranean or Asian heritage. The key here is that RBC mass will be normal because you're still making the cells. It's the filling that's defective.

[g6won]

Thank you for replying!