Red cell and plasma volumes in normal adults

Area of Science:

• Hematology
• Physiology
• Biostatistics

Background:

• Existing methods for predicting normal red cell and plasma volumes lack specificity for individual body dimensions.
• Limited data exists on the normal range of these volumes relative to body size in diverse populations.

Purpose of the Study:

• To calculate and present normal ranges for red cell volume and plasma volume based on body surface area.
• To compare observed normal values with those predicted by existing formulas.
• To provide a reliable reference for clinical assessment of red cell and plasma volumes.

Main Methods:

• Analysis of reported red cell and plasma volumes from 481 normal men and 303 normal women.
• Calculation of mean volumes and standard deviations (s.d.) stratified by body surface area and sex.
• Graphical plotting of mean volumes and 95% confidence limits against body surface area.

Main Results:

• Mean volumes and 95% confidence limits showed curvilinear relationships with body surface area.
• Standard deviations increased with mean volumes, while coefficients of variation remained constant at 11-12%.
• Observed mean values frequently differed from predictions of published formulas.

Conclusions:

• The study provides new, reliable graphs of normal red cell and plasma volumes correlated with body surface area.
• The established 11-12% coefficient of variation allows for the compilation of normal ranges for clinical comparison.
• These findings offer improved accuracy for assessing erythrocyte and plasma volumes in clinical practice.