Measuring Hematocrit/hemoglobin levels as a part of regular blood test, or complete blood count.
Hemoglobin is the iron-rich protein in red blood cells that carries oxygen to the body, and its low levels is a sign of anemia.
Hematocrit numbers, shows how big portion of blood volume is occupied with red blood cells.
Decreased levels of hematocrit, also, indicates possible anemia.
The CBC test, also, checks the number of red blood cells, and MCV (Mean corpuscular volume )a measurement of the average size of your RBCs.
In iron-deficiency anemia, for example, red blood cells usually are smaller than normal, and MCV will be low.

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