# Hemostasis Laboratory Diagnostics in Newborns

## TL;DR

This paper reviews how to accurately assess blood clotting in newborns, focusing on challenges and new testing methods.

## Contribution

The paper highlights the importance of neonatal age-specific coagulation standards and the emerging role of viscoelastic tests.

## Key findings

- Routine coagulation tests in newborns require neonatal-specific reference ranges.
- Hematocrit levels significantly affect coagulation test accuracy in newborns.
- Viscoelastic tests are gaining importance but lack standardization for neonatal use.

## Abstract

The hemostatic system in the newborn is a complex entity, characterized by dynamism in its development; therefore, the correct measurement of its potential is challenging. In this narrative review, we analyzed the current knowledge of the “developmental hemostasis” of the newborn; we also studied the performance of routine coagulation tests in its evaluation, with considerations about the establishment of neonatal age-specific normal ranges and about the role of preanalytical variables, in particular, hematocrit (which could represent an important cause of error); we also focused on the increasing importance of viscoelastic coagulation tests, which are becoming increasingly widespread (especially in some settings such as intensive care unit) and are able to quickly provide information about the hemostatic function of the newborn, even if they lack adequate standardization in the neonatal period.