Total red cell volume in healthy young males.

Regression equations of total red cell volume on body weight, body surface area, lean body mass, etc., are provided for a series of 79 normal male volunteer subjects. The regression of total red cell volume on a combination of height and weight provided the smallest standard error of the estimate and the largest correlation coefficient. The coefficient of variation was 1.6 percent between the first and second red cell volume determination in 31 of these subjects. The popular expression of total red cell volume in ml per kg remains unsatisfactory. It is recommended that a comparison be made between a measured total red cell volume and a predicted normal range derived from a regression using body surface area as the independent variable. A simplified graph is provided which clearly delineates normal from abnormal and should prove adequate for most clinical situations.