A bicentric cohort study comparing umbilical cord and neonatal blood samples for chemistry tests at birth

Abstract

Objectives: To compare umbilical cord and neonatal blood for chemistry tests upon admission to the neonatal intensive care unit (NICU).

Methods: We designed a prospective, bicentric cohort study enrolling newborns (n = 71) with a planned admission to the NICU. Paired samples of umbilical cord and infant's blood were collected, analyzed, and compared. An intraclass correlation coefficient (ICC) was calculated for a repeatability analysis, and a Bland-Altman analysis was performed to assess the agreement between the 2 methods of sampling. The multivariable coefficient of determination (R2) was reported to quantify the degree of correlation between the methods of measurement.

Results: The degree of agreement between the 2 sampling methods for chemistry tests was fair to good for high-sensitivity C-reactive protein (ICC = 0.79 [95% CI, 0.67-0.87]), phosphorus (ICC = 0.83 [95% CI, 0.73-0.90]), and albumin (ICC = 0.76 [95% CI, 0.60-0.86]), while it was good to excellent for γ-glutamyl transpeptidase (ICC = 0.95 [95% CI, 0.88-0.98]) and procalcitonin (ICC = 0.90 [95% CI, 0.76-0.96]).

Conclusions: Umbilical cord blood is a reliable replacement source for multiple chemistry tests at birth. This sampling method has the potential to minimize the risk of transfusion-requiring anemia in newborns and its associated complications. Further studies are warranted to assess the efficacy of this strategy in improving neonatal outcomes.

Keywords: blood draw; chemistry tests; neonatal blood; neonates; umbilical cord.