Lactate-to-albumin ratio, C-reactive protein-to-albumin ratio, and prognostic nutritional index in acute and critical care: A focused mini-review.

Risk stratification in acute and critical care increasingly relies on accessible biomarkers that capture multiple dimensions of physiological stress. Albumin-based composite biomarkers have gained attention because serum albumin reflects not only nutritional reserve but also systemic inflammation, hepatic synthetic capacity, endothelial permeability, capillary leakage, and resuscitation-related volume shifts. Among these indices, the lactate-to-albumin ratio, C-reactive protein-to-albumin ratio (CAR), and prognostic nutritional index (PNI) are particularly practical because they combine albumin with markers of tissue hypoperfusion, inflammatory burden, and immune-nutritional status. This focused mini-review presents a narrative synthesis of literature identified through targeted searches of PubMed, Web of Science, and Google Scholar using terms related to these indices and acute or critical care populations. Evidence suggests that elevated lactate-to-albumin and CARs and reduced PNI are generally associated with mortality, organ dysfunction, intensive care requirement, postoperative complications, and prolonged hospitalization in emergency department, intensive care, perioperative, infectious, cardiovascular, respiratory, gastrointestinal, trauma, and oncological settings. However, interpretation is limited by disease heterogeneity, variable sampling times, resuscitation-related albumin changes, hepatic dysfunction, chronic inflammation, inconsistent cutoff values, and the predominance of retrospective and observational evidence. These indices should therefore be interpreted as supportive prognostic markers within the broader clinical context rather than as replacements for clinical judgment or validated prognostic models.