What is mathematical relationship between hemoglobin and hematocrit value?

Hematocrit (Hct) and hemoglobin (Hb) are two important parameters measured in a complete blood count (CBC). They are related to each other and provide valuable information about the oxygen-carrying capacity of blood.

The mathematical relationship between hemoglobin and hematocrit can be expressed as follows:

Hct (%) = Hb (g/dL) / 3 × RBC count (million cells/μL)

Where:

Hct is the hematocrit value

Hb is the hemoglobin concentration

RBC count is the red blood cell count

For example, if a person has a hemoglobin level of 15 g/dL and a red blood cell count of 5 million cells/μL, their hematocrit can be calculated as follows:

Hct (%) = 15 g/dL / 3 × 5 million cells/μL

= 0.45 × 5

= 2.25

Therefore, the hematocrit value in this case would be 22.5%.

This mathematical relationship is useful in clinical practice as it allows clinicians to estimate one parameter if the other is known. It also helps in identifying abnormalities in either hematocrit or hemoglobin levels, which can indicate underlying medical conditions.