[Practical value of the measurement of red cell volume in anemia].

In most cases of anemia, haematocrit is a good index of the degree of the red blood cell mass decrease; however, in the patients with renal deficiency, hyposideremic anemia, or severe hemolysis, a variable response of the plasma volume to anemia makes any measurement of the hematocrit a poor index of the red cell mass; in patients with splenomegaly, an excess of plasma volume makes any measurement of the treatment. The direct measurement of the red cell mass appears to be useful in clinical practice in many cases with anemia.