Salivary lactate dehydrogenase levels can provide early diagnosis of hypoxic–ischaemic encephalopathy in neonates with birth asphyxia

Aim Timely detection of hypoxic–ischaemic encephalopathy ( HIE ) is crucial for selecting neonates who are likely to benefit from neuroprotective therapy. This study evaluated the efficacy of salivary lactate dehydrogenase ( LDH ) in the early diagnosis of HIE among neonates with perinatal asphyxia. Methods We prospectively enrolled 30 neonates who needed resuscitation at birth or had a history of delayed cry into the HIE group if they developed HIE within 12 h of birth. The control group comprised 30 neonates who had no evidence of HIE , but had intrapartum foetal distress or needed resuscitation at birth. LDH was measured using saliva samples collected within 12 h of birth. Results Salivary LDH was significantly higher in the HIE group, with a median of 2578 and an interquartile range ( IQR ) of 1379–3408 international units per litre ( IU /L), than in the control group (median 558.5, IQR : 348–924 IU /L, p < 0.001). The test demonstrated excellent discriminating ability: the area under the curve was 0.92 and the levels of 893 IU /L showed a sensitivity of 90% and a specificity of 73.3%. Conclusion Measuring salivary LDH among neonates with birth asphyxia provided an early and accurate diagnosis of HIE and could be used as a triage tool.