Albumin administration in internal medicine: A journey between effectiveness and futility

term albumin treatment Sepsis Resuscitation fluidA B S T R A C T Albumin is the most abundant circulating protein and provides about 70% of the plasma oncotic power.The molecule also carries many other biological functions (binding, transport and detoxification of endogenous and exogenous compounds, antioxidation, and modulation of inflammatory and immune responses).Hypoalbuminemia is a frequent finding in many diseases, representing usually only a biomarker of poor prognosis rather than a primary pathophysiological event.Despite that, albumin is prescribed in many conditions based on the assumption that correction of hypoalbuminemia would lead to clinical benefits for the patients.Unfortunately, many of these indications are not supported by scientific evidence (or have been even disproved), so that a large part of albumin use is nowadays still inappropriate.Decompensated cirrhosis is the clinical area where albumin administration has been extensively studied and solid recommendations can be made.Besides prevention and treatment of acute complications, long-term albumin administration in patients with ascites has emerged in the last decade has a potential new diseasemodifying treatment.In non-hepatological settings, albumin is widely used for fluid resuscitation in sepsis and critical illnesses, with no clear superiority over crystalloids.In many other conditions, scientific evidence supporting albumin prescription is weak or even absent.Thus, given its high cost and limited availability, action is needed to avoid the use of albumin for inappropriate and futile indications to ensure its availability in those conditions for which albumin has been demonstrated to have a real effectiveness and an advantage for the patient.Human albumin is the most abundant circulating protein and accounts for approximately 50-60% of all total plasma proteins in healthy individuals.The molecule is composed of 585 amino acids organised into three homologous domains (I, II and III), each of which containing two distinct subdomains.The liver is the only site of production, with the hepatocytes entering into the blood circulation about 9-12 gs of albumin every day [1,2].In physiological conditions, albumin synthesis involve only 20-30% of hepatocytes, therefore there is a large functional reserve allowing to increase it by 3-4 times when needed.The catabolism of the molecule is ubiquitous and takes place at the level of vascular endothelia, muscle, skin and kidney at a daily rate that equals hepatic synthesis.The circulatory half-life of the protein is about 16-18 h, since every hour 4-5% of albumin leaves the intravascular compartment, and then returns to it via the lymphatic system.The overall half-life is about