The total blood volume can be calculated if the red cell volume and the whole blood hematocrit are known.


total blood volume in liters =

= (red cell volume liters) / (0.9 * (venous hematocrit))



• 0.9 is the ratio for [(whole blood hematocrit) / (venous hematocrit)]


total blood volume in liters =

= (plasma volume in liters) * 100 / (100 - (hematocrit as a percent))


• With hematocrits > 55% this method underestimates the TBV.

• If TBV is based on total body water or lean body mass there is no difference between the values for obese and for lean persons


To read more or access our algorithms and calculators, please log in or register.