Evaluation of heparinized syringes for measuring newborn metabolites in neonates with a central arterial line

Newborn metabolic screening is emerging as a novel method for predicting neonatal morbidity and mortality in neonates born very preterm (<32 weeks gestation). The purpose of our study was to determine if blood collected by an electrolyte-balanced dry lithium heparin syringe, as is routine for blood gas measurements, affects targeted metabolite and biomarker levels. Two blood samples (one collected with a heparinized syringe and the other with a non-heparinized syringe) were obtained at the same time from 20 infants with a central arterial line and tested for 49 metabolites and biomarkers using standard procedures for newborn screening. Overall, the median metabolite levels did not significantly differ by syringe type. However, there was wide variability, particularly for amino acids and immunoreactive trypsinogen, for individual paired samples and therefore, consideration should be given to sample collection when using these metabolites in prediction models of neonatal morbidity and mortality.

Automated summary

Newborn metabolic screening is a promising method for predicting neonatal morbidity and mortality. However, the type of syringe used for blood collection, specifically in this study the electrolyte-balanced dry lithium heparin syringe, may have an impact on the levels of targeted metabolites and biomarkers. While the median levels did not differ significantly by syringe type, there was considerable variability for certain metabolites, suggesting the need to consider sample collection methods when utilizing these markers in prediction models for neonatal outcomes.