Serum albumin in the context of Plasma (blood)

Acute liver failure is the appearance of severe complications rapidly after the first signs (such as jaundice) of liver disease, and indicates that the liver has sustained severe damage (loss of function of 80–90% of liver cells). The complications are hepatic encephalopathy and impaired protein synthesis (as measured by the levels of serum albumin and the prothrombin time in the blood). The 1993 classification defines hyperacute as within 1 week, acute as 8–28 days, and subacute as 4–12 weeks; both the speed with which the disease develops and the underlying cause strongly affect outcomes.

Blood plasma is a light amber-colored liquid component of blood in which blood cells are absent, but which contains proteins and other constituents of whole blood in suspension. It makes up about 55% of the body's total blood volume. It is the intravascular part of extracellular fluid (all body fluid outside cells). It is mostly water (up to 95% by volume), and contains important dissolved proteins (6–8%; e.g., serum albumins, globulins, and fibrinogen), glucose, clotting factors, electrolytes (Na
, Ca
, Mg
, HCO₃, Cl
, etc.), hormones, carbon dioxide (plasma being the main medium for excretory product transportation), and oxygen. It plays a vital role in an intravascular osmotic effect that keeps electrolyte concentration balanced and protects the body from infection and other blood-related disorders.

Blood plasma can be separated from whole blood through blood fractionation, by adding an anticoagulant to a tube filled with blood, which is spun in a centrifuge until the blood cells fall to the bottom of the tube. The blood plasma is then poured or drawn off. For point-of-care testing applications, plasma can be extracted from whole blood via filtration or via agglutination to allow for rapid testing of specific biomarkers. Blood plasma has a density of approximately 1,025 kg/m (1.025 g/ml). Blood serum is blood plasma without clotting factors. Plasmapheresis is a medical therapy that involves blood plasma extraction, treatment, and reintegration.

Diabetic nephropathy, also known as diabetic kidney disease, is the chronic loss of kidney function occurring in those with diabetes mellitus. Diabetic nephropathy is the leading cause of chronic kidney disease (CKD), and end-stage renal disease (ESRD) globally. The triad of protein leaking into the urine (proteinuria or albuminuria), rising blood pressure with hypertension and then falling renal function is common to many forms of CKD. Protein loss in the urine due to damage of the glomeruli may become massive, and cause a low serum albumin with resulting generalized body swelling (edema) so called nephrotic syndrome. Likewise, the estimated glomerular filtration rate (eGFR) may progressively fall from a normal of over 90 ml/min/1.73m to less than 15, at which point the patient is said to have end-stage renal disease. It usually is slowly progressive over years.

Pathophysiologic abnormalities in diabetic nephropathy usually begin with long-standing poorly controlled blood glucose levels. This is followed by multiple changes in the filtration units of the kidneys, the nephrons. (There are normally about 750,000–1.5 million nephrons in each adult kidney). Initially, there is constriction of the efferent arterioles and dilation of afferent arterioles, with resulting glomerular capillary hypertension and hyperfiltration particularly as nephrons become obsolescent and the adaption of hyperfiltration paradoxically causes further shear stress related damage to the delicate glomerular capillaries, further proteinuria, rising blood pressure and a vicious circle of additional nephron damage and decline in overall renal function. Concurrently, there are changes within the glomerulus itself: these include a thickening of the basement membrane, a widening of the slit membranes of the podocytes, an increase in the number of mesangial cells, and an increase in mesangial matrix. This matrix invades the glomerular capillaries and produces deposits called Kimmelstiel-Wilson nodules. The mesangial cells and matrix can progressively expand and consume the entire glomerulus, shutting off filtration.

Calcium ions (Ca) contribute to the physiology and biochemistry of organisms' cells. They play an important role in signal transduction pathways, where they act as a second messenger, in neurotransmitter release from neurons, in contraction of all muscle cell types, and in fertilization. Many enzymes require calcium ions as a cofactor, including several of the coagulation factors. Extracellular calcium is also important for maintaining the potential difference across excitable cell membranes, as well as proper bone formation.

Plasma calcium levels in mammals are tightly regulated, with bone acting as the major mineral storage site. Calcium ions, Ca, are released from bone into the bloodstream under controlled conditions. Calcium is transported through the bloodstream as dissolved ions or bound to proteins such as serum albumin. Parathyroid hormone secreted by the parathyroid gland regulates the resorption of Ca from bone, reabsorption in the kidney back into circulation, and increases in the activation of vitamin D₃ to calcitriol. Calcitriol, the active form of vitamin D₃, promotes absorption of calcium from the intestines and bones. Calcitriol also plays a key role in upregulating levels of intracellular calcium, and high levels of this ion appear to be protective against cancers of the breast and prostate. The suppression of calcitriol by excessive dietary calcium is believed to be the major mechanism for the potential link between dairy and cancer. However, the vitamin D present in many dairy products may help compensate for this deleterious effect of high-calcium diets by increasing serum calcitriol levels. Calcitonin secreted from the parafollicular cells of the thyroid gland also affects calcium levels by opposing parathyroid hormone; however, its physiological significance in humans is in dispute.

Plasma proteins, sometimes referred to as blood proteins, are proteins present in blood plasma. They perform many different functions, including transport of hormones, vitamins and minerals in activity and functioning of the immune system. Other blood proteins act as enzymes, complement, components, protease inhibitors or kinin precursors. Contrary to popular belief, haemoglobin is not a blood protein, as it is carried within red blood cells, rather than in the blood serum.

Serum albumin accounts for 55% of blood proteins, is a major contributor to maintaining the oncotic pressure of plasma and assists, as a carrier, in the transport of lipids and steroid hormones. Globulins make up 38% of blood proteins and transport ions, hormones, and lipids assisting in immune function. Fibrinogen comprises 7% of blood proteins; conversion of fibrinogen to insoluble fibrin is essential for blood clotting. The remainder of the plasma proteins (1%) are regulatory proteins, such as enzymes, proenzymes, and hormones. All blood proteins are synthesized in liver except for the gamma globulins.

Albumin is a family of globular proteins, the most common of which are the serum albumins. All of the proteins of the albumin family are water-soluble, moderately soluble in concentrated salt solutions, and experience heat denaturation. Albumins are commonly found in blood plasma and differ from other blood proteins in that they are not glycosylated. Substances containing albumins are called albuminoids.

A number of blood transport proteins are evolutionarily related in the albumin family, including serum albumin, alpha-fetoprotein, vitamin D-binding protein and afamin. This family is only found in vertebrates.