Blood plasma is used to treat a surprisingly wide range of medical conditions, from massive bleeding after a car accident to genetic lung diseases to immune system disorders. This straw-colored liquid makes up about 55% of your total blood volume and serves as the raw material for dozens of life-saving therapies. Its value comes from what’s dissolved in it: plasma is roughly 92% water, with the remaining 8% made up of proteins like albumin, clotting factors, and antibodies that can be separated out and turned into targeted treatments.
Stopping Dangerous Bleeding in Trauma
One of the most critical uses of plasma is in emergency rooms and operating theaters, where it helps restore the blood’s ability to clot in patients who are hemorrhaging. When someone loses a large volume of blood from a severe injury, surgery, or childbirth, they don’t just lose red blood cells. They also lose the clotting proteins that prevent uncontrolled bleeding. Transfusing plasma directly replaces those proteins and helps the body form clots again.
In major trauma, doctors now often give plasma alongside red blood cells from the very start of resuscitation rather than relying on saline or other clear fluids. This approach reflects a shift in emergency care: large volumes of saline can actually dilute the remaining clotting factors and make bleeding worse. Current practice in severely injured patients typically uses plasma and red blood cells in a fixed ratio, with some trauma centers aiming for roughly equal amounts of each.
Treating Hemophilia and Clotting Disorders
People with hemophilia are missing one of the specific proteins their blood needs to clot. Hemophilia A involves a shortage of one clotting factor, while hemophilia B involves a different one. Without treatment, even minor injuries can cause prolonged, dangerous bleeding.
Plasma is the original source of the clotting factor concentrates used to treat hemophilia. To make these products, donated plasma from many individuals is pooled together and processed to isolate the needed clotting proteins. The result is a freeze-dried concentrate that patients can inject into a vein, either on a regular schedule to prevent bleeding episodes or on demand when bleeding starts. Recombinant (lab-made) versions of these clotting factors now exist as well, but plasma-derived concentrates remain an important option worldwide.
Supporting the Immune System
Plasma contains antibodies, the immune proteins your body produces to fight infections. When these antibodies are collected and concentrated from thousands of donations, they become a therapy called intravenous immunoglobulin, or IVIG. This product is given to people whose immune systems can’t produce enough antibodies on their own.
That includes people born with immune deficiencies, but it also covers a much larger group: patients whose immune function has been suppressed by chemotherapy, organ transplant medications, or conditions like HIV. IVIG is also used to calm an overactive immune system in autoimmune diseases, including Kawasaki disease in children, lupus, certain types of muscle inflammation, and some forms of nerve damage. It works in two directions, boosting immunity when it’s too weak and dampening it when it’s attacking the body’s own tissues.
Albumin Therapy for Liver Disease
Albumin is the most abundant protein in plasma, and it plays a key role in keeping fluid inside your blood vessels rather than leaking into surrounding tissues. In people with advanced liver disease (cirrhosis), the liver can no longer produce enough albumin. Fluid accumulates in the abdomen, blood pressure drops, and the kidneys start to fail.
Plasma-derived albumin is a cornerstone of managing these complications. When doctors drain large volumes of abdominal fluid from a patient with cirrhosis, albumin infusions help prevent a dangerous drop in blood pressure afterward. Albumin is also given alongside antibiotics when patients with cirrhosis develop a serious abdominal infection called spontaneous bacterial peritonitis, where it significantly reduces the risk of kidney failure and death. In hepatorenal syndrome, a condition where failing liver function drags kidney function down with it, albumin is combined with medications that constrict blood vessels to try to restore kidney blood flow.
Beyond liver disease, albumin is sometimes used to supplement fluid resuscitation in patients with severe infections or shock who aren’t responding well to standard IV fluids alone.
Treating a Genetic Lung Disease
Alpha-1 antitrypsin deficiency is an inherited condition in which the body doesn’t make enough of a protective protein that shields the lungs from damage. Without it, the lungs gradually develop emphysema, often at a younger age than typical smoking-related cases. The only specific treatment is augmentation therapy: weekly intravenous infusions of the missing protein, purified from donated human plasma.
Multiple clinical trials have shown that this therapy slows the progression of emphysema as measured by CT scans of lung tissue density. The largest of these, called the RAPID trial, followed 180 patients over two years and confirmed a measurable reduction in lung tissue loss. The treatment is considered safe, with side effect rates similar to placebo in controlled studies. It doesn’t reverse existing damage, but for eligible patients it can meaningfully slow the decline in lung function over time.
Convalescent Plasma for Infectious Disease
When someone recovers from a viral infection, their plasma is rich in antibodies specific to that virus. Transfusing this “convalescent” plasma into a patient still fighting the same infection gives their immune system a head start. The concept is not new. It has been used during outbreaks of pandemic influenza, Ebola, and Lassa fever.
COVID-19 brought convalescent plasma into mainstream awareness. In December 2024, the FDA approved its use specifically for treating COVID-19 in people with weakened immune systems. The therapy is most useful when no vaccine or proven treatment exists for an emerging infection, or when a patient’s immune system simply can’t mount a fast enough response on its own.
How Plasma Products Are Made Safe
Because plasma is pooled from many donors, manufacturing includes multiple layers of safety testing and pathogen removal. Before plasma even reaches a processing facility, every donor is screened and every donation is tested for infectious diseases.
During manufacturing, the fractionation process itself provides a degree of safety. Changes in temperature, pH, and alcohol concentration during protein separation physically disassociate viruses from the proteins being collected. Beyond that, manufacturers typically layer on two or more additional methods. Solvent-detergent treatment disrupts the outer membranes of viruses like HIV and hepatitis B and C. Heat treatment, whether dry, steam, or pasteurization, inactivates pathogens at specific temperatures and durations calibrated to preserve the product’s biological activity. Nanofiltration physically strains out viral particles based on size.
Some viruses without lipid envelopes, like parvovirus B19 and hepatitis A, are harder to inactivate. Manufacturers address this through genetic testing of plasma pools before processing begins, removing any units with high viral levels. Every finished product is also tested for sterility before it’s released.
Where Donated Plasma Comes From
Plasma for medical products comes from two main sources. Some is separated from whole blood donations at blood banks. The rest, called “source plasma,” is collected through a process called plasmapheresis, where a machine draws blood, separates out the plasma, and returns the red blood cells and other components to the donor. This process takes longer than a standard blood donation but allows much more plasma to be collected at once and can be done more frequently than whole blood donation, since the donor keeps their red blood cells.
The demand for plasma-derived therapies continues to grow, particularly for immunoglobulin products. The United States is the world’s largest supplier of source plasma, and paid plasma donation centers are a major part of that supply chain. A single donation can contribute to treatments for bleeding disorders, immune deficiencies, liver disease, and more, making plasma one of the most versatile biological materials in modern medicine.