STUDIES ON ERYTHRO-KINETICS IN INFANCY .9. PREDICTION OF RED CELL VOLUME FROM VENOUS HAEMATOCRIT IN EARLY INFANCY

Sixty‐six determinations of circulating red cell volume (RCV) were performed in 24 normal fullterm and 16 normal premature infants aged 4 hours to 138 days. The correlation between venous haematocrit (vHct) and RCV/kg was analysed. Within the range of vHct studied, 23–67%, the relationship was linear according to the equation: RCV/kg= ‐12.3 + 1.02 vHct. No significant difference in slope or position of the regression lines was found between the full‐term and premature infants. A comparison with adult individuals, taken from the literature, showed an almost identical relationship. The equation is proposed as a formula for prediction of RCV in full‐term and premature infants during the first five months of life. The standard error of estimate for prediction from this formula is approximately 10%. Copyright © 1968, Wiley Blackwell. All rights reserved