Diagnostic value of lactate/albumin and lactate dehydrogenase/albumin ratios in newborns with hypoxic-ischemic encephalopathy

OBJECTIVES: Early assessment of hypoxic-ischemic encephalopathy (HIE) severity is crucial, as therapeutic hypothermia should be initiated within the first 6 h of life. This study aimed to evaluate early postnatal lactate, albumin, and lactate dehydrogenase (LDH) levels, together with derived lactate/albumin (L/A) and LDH/albumin (LDH/A) ratios, and to assess their discriminative performance in neonates with moderate-to-severe HIE treated with therapeutic hypothermia. METHODS: This retrospective case-control study was conducted in a tertiary-quaternary neonatal intensive care unit between January 2022 and December 2024. Term neonates (≥36 weeks' gestation) diagnosed with moderate-to-severe HIE (stage II-III) according to Thompson scoring and treated with therapeutic hypothermia were included. Healthy term neonates without perinatal asphyxia served as the control group. Early postnatal serum lactate, albumin, and LDH levels obtained within the first 6 h of life were recorded, and L/A and LDH/A ratios were calculated. Group comparisons were performed, and the discriminative performance of the biomarkers was evaluated using receiver operating characteristic (ROC) curve analysis. RESULTS: A total of 53 neonates with HIE and 84 healthy term controls were analyzed. Serum lactate and LDH levels, as well as L/A and LDH/A ratios, were significantly higher in the HIE group compared with controls (p<0.001). ROC analysis demonstrated high discriminative performance for lactate (AUC: 0.987) and LDH/A ratio (AUC: 0.973), while the L/A ratio showed moderate discriminative ability (AUC: 0.793). Albumin alone did not demonstrate significant discriminative value. CONCLUSIONS: Early postnatal lactate- and LDH-based composite ratios, particularly the LDH/albumin ratio, may serve as useful supportive biomarkers for the early identification of moderate-to-severe HIE. These readily available indices could assist clinical decision-making when advanced neurodiagnostic evaluations are delayed. Further prospective and multicenter studies are warranted to validate their diagnostic utility.