The PARENT study will examine platelet and endothelial associated proteins in preterm infants being investigated for late onset sepsis (LOS) to see if infants with fulminant sepsis can be prospectively identified using these markers

Infants who are less than 34 weeks corrected gestational age at time of birth will be enrolled prior to any late onset sepsis investigations. At point of clinical concern for the development of late onset sepsis a 0.5-1.3ml sodium citrate sample will be taken. A targeted proteomic analysis using mass spectroscopy and flow cytometry will be performed and compared with the clinical diagnosis of the infant to examine if this can be used prospectively to identify infants with late onset sepsis

Inclusion Criteria:

• <34 weeks corrected gestational age at birth
• Under investigation for Late Onset Neonatal Sepsis (Sepsis of onset >72 hours of age)

Exclusion Criteria:

• Major congenital anomaly
• Suspicion of an underlying haematological disorder affecting platelets
• Have received a platelet transfusion prior to sampling

Preterm infants less than 34 weeks corrected gestational age at birth who are undergoing investigations for late onset sepsis

Summary data will be available to other researchers, individual data will be withheld as much as required by GDPR requirements