Brans et al used the hematocrit of blood drawn from the umbilical vein to predict red blood cell volume in a neonate. The authors are from the University of Texas at San Antonio.


Subject: neonate (ranged from 36 to 43 weeks of gestation, with average 40 weeks)



(1) hematocrit of umbilical venous blood as a percent from 0 to 100

(2) body weight of the neonate in kilograms


estimated red blood cell volume in mL per kg =

= (2.12 * (hematocrit in percent)) - 70


red blood cell volume in mL =

= (estimated red blood cell volume in mL/kg) * (body weight in kilograms)



• r = 0.79 and p < 0.001

• This may not be as accurate in a premature infant.


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