Sepsis remains a leading cause of mortality in the neonatal population, and currently, there is still no consensus on an accurate biomarker that can aid prompt diagnosis. This review focuses on studies investigating biomarkers for late-onset neonatal sepsis specifically. We discuss the current evidence for traditionally used biomarkers and present recent developments on more novel markers. Suitable articles were selected from PubMed, Embase, Medline, Cochrane Handbook of Systematic Reviews, and ScienceDirect. Inclusion criteria were studies published from 2010 to 2020. Exclusion criteria were animal model-based studies. Keywords in search strategy were late-onset neonatal sepsis + biomarkers + diagnosis. Evidence is growing increasingly weak for commonly studied biomarkers such as C-reactive protein (CRP) and procalcitonin (PCT). Levels of markers such as Serum Amyloid A and Neutrophil CD64 increase more rapidly post-onset of infection compared to CRP. Moreover, this review found that the more novel biomarkers discussed such as presepsin and endocan may show superior and more promising potential as diagnostic markers. However, larger studies over multicenters are deemed essential to ascertain the ideal biomarker.

Background: Perinatal asphyxia (PA) which may result in hypoxic ischaemic encephalopathy (HIE) affects four million neonates worldwide and accounts for the death of one million of affected babies. The science of metabolomics has become an area of growing interest in neonatal research, with a potential role in identifying useful biomarkers that can accurately predict injury severity in perinatal asphyxia and HIE. The aim of this review is to look at the evidence of the usefulness of urine metabolomics in predicting outcome in PA/HIE. Methods: The key words used in the advanced search ‘urine metabolomics’ AND ‘perinatal asphyxia’ OR ‘hypoxic ischaemic encephalopathy’, yielded 13 articles. Results: Of the selected thirteen studies, 38% (n = 5) were human studies, 31% (n= 4) were animal studies and 31% (n = 4) were review articles. The studies confirmed the involvement of known pathways in the development of PA/HIE, primarily the Krebs cycle evidenced by accumulation of TCA cycle intermediates (citrate, α-ketoglutarate, succinate) and anaerobic pathways indicated by increased lactate. Other pathways involved include amino acid and carbohydrate pathways. Conclusion: Metabolomic studies so far are promising in highlighting potential biomarker profiles in PA/HIE. Further research is necessary to further clarify the role of identified metabolites in predicting outcome and prognosis in neonates affected by PA/HIE.