Albumin dialysis is a specialized blood purification therapy designed to remove specific toxins that accumulate during liver failure. Unlike standard dialysis, which primarily targets water-soluble waste, this procedure focuses on substances that bind to albumin, a protein in the blood. It functions as an external liver support system to cleanse the blood when the liver cannot. This therapy is used in intensive care settings for patients with severe liver dysfunction.
The Role of Albumin in Toxin Removal
Albumin is the most abundant protein in blood plasma and is synthesized by the liver. One of its primary functions is to act as a transport vehicle, binding to and carrying molecules like hormones and fatty acids throughout the bloodstream. This is a normal part of how the body functions.
During liver failure, this transport function becomes central to detoxification. A damaged liver loses its ability to process certain waste products, such as bilirubin, bile acids, and aromatic amino acids. Because these substances are not easily dissolved in water, they build up and latch onto albumin molecules in the blood. This process forms albumin-bound toxins, which accumulate to dangerous levels and contribute to the severe complications associated with liver failure.
The Albumin Dialysis Procedure
The most common method is the Molecular Adsorbent Recirculating System (MARS). This system uses two distinct fluid circuits to cleanse the blood. The procedure takes place at the patient’s bedside, often in an intensive care unit, with treatments lasting eight hours over several consecutive days.
The first circuit draws the patient’s blood and passes it through a high-permeability dialyzer. On the other side of this filter’s membrane, a sterile, albumin-rich solution, known as the dialysate, flows in the opposite direction. Toxins in the patient’s blood move across the membrane toward the low-concentration albumin solution, transferring from the patient’s albumin to the clean albumin in the dialysate.
When the albumin solution becomes saturated with toxins, it is diverted into a second, regenerative circuit. The solution passes through a standard dialysis filter to remove water-soluble wastes and then through two adsorbent cartridges with activated charcoal and an anion-exchange resin. These cartridges strip the bound toxins from the albumin, which is then recirculated back to the first circuit to collect more toxins.
Conditions Treated with Albumin Dialysis
Albumin dialysis is primarily used for conditions involving severe liver dysfunction, such as acute liver failure and acute-on-chronic liver failure. In these states, the liver is overwhelmed and unable to clear accumulating albumin-bound substances. The therapy manages the resulting toxemia to stabilize the patient’s condition.
The accumulation of these toxins is linked to serious health consequences, most notably hepatic encephalopathy, where toxins affect brain function, leading to confusion, disorientation, and coma. By removing substances like aromatic amino acids and ammonia, albumin dialysis can improve or reverse these symptoms. The procedure also helps manage severe jaundice by clearing excess bilirubin and can alleviate intractable itching caused by high levels of bile acids.
This therapy is a supportive measure, not a cure. It acts as a “bridge” therapy, giving the native liver time to recover or keeping a patient stable until a liver transplant is possible. It is also used for overdoses of certain protein-bound drugs.
Comparison to Standard Hemodialysis
The differences between albumin dialysis and standard hemodialysis lie in the toxins they remove and the organs they support. Standard hemodialysis is a form of artificial kidney support. It filters small, water-soluble waste products like urea and creatinine from the blood, which a healthy kidney excretes.
Albumin dialysis, in contrast, is a form of artificial liver support. Its purpose is to remove larger, lipid-soluble toxins bound to albumin proteins, which a healthy liver would normally clear. Standard hemodialysis membranes do not permit the passage of these large, protein-bound complexes, making the therapy ineffective for this specific detoxification task.
The underlying mechanics also differ. Standard hemodialysis uses a single-pass system where blood is filtered against a clean dialysate solution, and the used, waste-filled dialysate is then discarded. Albumin dialysis systems like MARS employ a dual-circuit, regenerative process where the albumin-rich dialysate is continuously cleaned and recirculated.