Sepsis is a life-threatening condition resulting from a dysregulated immune response to infection, frequently encountered in ICU patients. Despite advances in medical care, it remains a significant global health issue, affecting over 30 million individuals annually with a mortality rate of 17%. The condition is especially prevalent and severe in the elderly, due to age-related immune dysfunction and prolonged inflammatory responses, leading to increased mortality.

Serum albumin (ALB), the most abundant plasma protein, plays a vital role in maintaining osmotic pressure and transporting substances, and is widely used as a prognostic marker in critically ill patients. Hypoalbuminemia is common in sepsis and is associated with poor outcomes. Hematocrit (HCT), which reflects the proportion of red blood cells, may increase due to hemoconcentration or chronic hypoxia and is also recognized as a potential predictor of mortality in sepsis.

Both HCT and ALB levels are normally stable in healthy individuals but may fluctuate significantly in sepsis due to increased capillary permeability, inflammation, metabolic changes, and blood loss. The difference between HCT (%) and ALB (g/L), referred to as the HCT-ALB difference, has emerged as a potentially useful marker for assessing disease severity and prognosis in infectious conditions