Blood plasma

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.[1] 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),[2] glucose, clotting factors, electrolytes (Na⁺
, Ca²⁺
, Mg²⁺
, 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.[3]

Blood plasma is separated from the blood by spinning a vessel of fresh blood containing an anticoagulant in a centrifuge until the blood cells fall to the bottom of the tube. The blood plasma is then poured or drawn off.[4] For point-of-care testing applications, plasma can be extracted from whole blood via filtration[5] or via agglutination[6] to allow for rapid testing of specific biomarkers. Blood plasma has a density of approximately 1,025 kg/m³ (1.025 g/ml).[7] Blood serum is blood plasma without clotting factors.[4] Plasmapheresis is a medical therapy that involves blood plasma extraction, treatment, and reintegration.

Fresh frozen plasma is on the WHO Model List of Essential Medicines, the most important medications needed in a basic health system.[8] It is of critical importance in the treatment of many types of trauma which result in blood loss, and is therefore kept stocked universally in all medical facilities capable of treating trauma (e.g., trauma centers, hospitals, and ambulances) or that pose a risk of patient blood loss such as surgical suite facilities.