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Assess your hematocrit level - the percentage of blood volume made up of red blood cells
Also known as Packed Cell Volume (PCV)
Hematocrit ≈ Hemoglobin × 3
This rule of thumb helps estimate one value from the other
Hematocrit (Hct), also called Packed Cell Volume (PCV), measures the percentage of your blood volume that is made up of red blood cells. If your hematocrit is 45%, it means 45% of your blood volume consists of red blood cells, with the rest being plasma and other components.
Hematocrit is part of a complete blood count (CBC) and helps diagnose anemia, polycythemia, dehydration, and other conditions affecting red blood cell production or destruction.
Blood is drawn and placed in a centrifuge that spins at high speed. Red cells settle to the bottom, and the percentage of the total volume they occupy is the hematocrit. Modern labs often calculate it from other CBC values.
During pregnancy, blood volume increases significantly, but plasma volume increases more than red cell volume, diluting the hematocrit. This is called physiological anemia of pregnancy and is normal.
Hematocrit measures the percentage of blood volume occupied by red cells, while hemoglobin measures the oxygen-carrying protein inside those cells. Both indicate red cell status, and hematocrit is roughly 3× the hemoglobin value.