Blood fractionation

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Blood components after centrifugation. Blood-centrifugation-scheme.png
Blood components after centrifugation.
When blood is collected into a serum-separating tube (SST) and centrifuged, the serum becomes isolated from the red blood cells by a gel acting as a physical barrier to prevent inadvertent remixing of the components. Sstvacutainer small.jpg
When blood is collected into a serum-separating tube (SST) and centrifuged, the serum becomes isolated from the red blood cells by a gel acting as a physical barrier to prevent inadvertent remixing of the components.

Blood fractionation is the process of fractionating whole blood, or separating it into its component parts. This is typically done by centrifuging the blood.

Contents

The resulting components are:

Serum separation tubes (SSTs) are tubes used in phlebotomy containing a silicone gel; when centrifuged the silicone gel forms a layer on top of the buffy coat, allowing the blood serum to be removed more effectively for testing and related purposes.

As an alternative to energy-consuming centrifugation, more energy-efficient technologies have been studied, such as ultrasonic fractionation. [1]

Plasma protein fractionation

Plasma proteins are separated by using the inherent differences of each protein. Fractionation involves changing the conditions of the pooled plasma (e.g., the temperature or the acidity) so that proteins that are normally dissolved in the plasma fluid become insoluble, forming large clumps, called precipitate. The insoluble protein can be collected by centrifugation. One of the very effective ways for carrying out this process is the addition of alcohol to the plasma membrane pool while simultaneously cooling the pool. This process is sometimes called cold alcohol fractionation or ethanol fractionation. It was described by and bears the eponym of Dr Edwin J. Cohn. This procedure is carried out in a series of steps so that a single pool of plasma yields several different protein products, such as albumin and immune globulin. [2] [3] Human serum albumin prepared by this process is used in some vaccines, for treating burn victims, and other medical applications.

See also

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<span class="mw-page-title-main">Clinical chemistry</span> Area of clinical pathology that is generally concerned with analysis of bodily fluids

Clinical chemistry is a division in medical laboratory sciences focusing on qualitative tests of important compounds, referred to as analytes or markers, in bodily fluids and tissues using analytical techniques and specialized instruments. This interdisciplinary field includes knowledge from medicine, biology, chemistry, biomedical engineering, informatics, and an applied form of biochemistry.

<span class="mw-page-title-main">Blood plasma</span> Liquid component of blood

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. It is mostly water, and contains important dissolved proteins, glucose, clotting factors, electrolytes, hormones, carbon dioxide, 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.

<span class="mw-page-title-main">Vacutainer</span> Type of blood collection equipment for medical testing

A vacutainer blood collection tube is a sterile glass or plastic test tube with a colored rubber stopper creating a vacuum seal inside of the tube, facilitating the drawing of a predetermined volume of liquid. Vacutainer tubes may contain additives designed to stabilize and preserve the specimen prior to analytical testing. Tubes are available with a safety-engineered stopper, with a variety of labeling options and draw volumes. The color of the top indicates the additives in the vial.

<span class="mw-page-title-main">Serum protein electrophoresis</span> Laboratory test

Serum protein electrophoresis is a laboratory test that examines specific proteins in the blood called globulins. The most common indications for a serum protein electrophoresis test are to diagnose or monitor multiple myeloma, a monoclonal gammopathy of uncertain significance (MGUS), or further investigate a discrepancy between a low albumin and a relatively high total protein. Unexplained bone pain, anemia, proteinuria, chronic kidney disease, and hypercalcemia are also signs of multiple myeloma, and indications for SPE. Blood must first be collected, usually into an airtight vial or syringe. Electrophoresis is a laboratory technique in which the blood serum is applied to either an acetate membrane soaked in a liquid buffer, or to a buffered agarose gel matrix, or into liquid in a capillary tube, and exposed to an electric current to separate the serum protein components into five major fractions by size and electrical charge: serum albumin, alpha-1 globulins, alpha-2 globulins, beta 1 and 2 globulins, and gamma globulins.

<span class="mw-page-title-main">Serum (blood)</span> Fluid and solute component of blood

Serum is the fluid and solute component of blood which does not play a role in clotting. It may be defined as blood plasma without the clotting factors, or as blood with all cells and clotting factors removed. Serum includes all proteins not used in blood clotting; all electrolytes, antibodies, antigens, hormones; and any exogenous substances. Serum does not contain white blood cells (leukocytes), red blood cells (erythrocytes), platelets, or clotting factors.

The globulins are a family of globular proteins that have higher molecular weights than albumins and are insoluble in pure water but dissolve in dilute salt solutions. Some globulins are produced in the liver, while others are made by the immune system. Globulins, albumins, and fibrinogen are the major blood proteins. The normal concentration of globulins in human blood is about 2.6-3.5 g/dL.

Blood-proteins, also termed plasma proteins, are proteins present in blood plasma. They serve many different functions, including transport of lipids, 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.

<span class="mw-page-title-main">Fractionation</span> Method of separating components of a mixture via phase transition

Fractionation is a separation process in which a certain quantity of a mixture is divided during a phase transition, into a number of smaller quantities (fractions) in which the composition varies according to a gradient. Fractions are collected based on differences in a specific property of the individual components. A common trait in fractionations is the need to find an optimum between the amount of fractions collected and the desired purity in each fraction. Fractionation makes it possible to isolate more than two components in a mixture in a single run. This property sets it apart from other separation techniques.

<span class="mw-page-title-main">Apheresis</span> Medical techniques to separate one or more components of blood

Apheresis is a medical technology in which the blood of a person is passed through an apparatus that separates out one particular constituent and returns the remainder to the circulation. It is thus an extracorporeal therapy.

<span class="mw-page-title-main">Plasmapheresis</span> Removal, treatment and return of blood plasma

Plasmapheresis is the removal, treatment, and return or exchange of blood plasma or components thereof from and to the blood circulation. It is thus an extracorporeal therapy, a medical procedure performed outside the body.

Capacitation is the penultimate step in the maturation of mammalian spermatozoa and is required to render them competent to fertilize an oocyte. This step is a biochemical event; the sperm move normally and look mature prior to capacitation. In vivo, capacitation occurs after ejaculation, when the spermatozoa leave the vagina and enter the superior female reproductive tract. The uterus aids in the steps of capacitation by secreting sterol-binding albumin, lipoproteins, and proteolytic and glycosidasic enzymes such as heparin.

<span class="mw-page-title-main">Ficoll</span>

Ficoll is a neutral, highly branched, high-mass, hydrophilic polysaccharide which dissolves readily in aqueous solutions. Ficoll radii range from 2 to 7 nm. It is prepared by reaction of the polysaccharide with epichlorohydrin. Ficoll is a registered trademark owned by GE Healthcare companies.

<span class="mw-page-title-main">Serum albumin</span> Type of globular protein produced by the liver

Serum albumin, often referred to simply as blood albumin, is an albumin found in vertebrate blood. Human serum albumin is encoded by the ALB gene. Other mammalian forms, such as bovine serum albumin, are chemically similar.

<span class="mw-page-title-main">Monoclonal gammopathy</span> Medical condition

Monoclonal gammopathy, also known as paraproteinemia, is the presence of excessive amounts of myeloma protein or monoclonal gamma globulin in the blood. It is usually due to an underlying immunoproliferative disorder or hematologic neoplasms, especially multiple myeloma. It is sometimes considered equivalent to plasma cell dyscrasia. The most common form of the disease is monoclonal gammopathy of undetermined significance.

<span class="mw-page-title-main">Bovine serum albumin</span> Serum albumin protein derived from cows

Bovine serum albumin is a serum albumin protein derived from cows. It is often used as a protein concentration standard in lab experiments.

<span class="mw-page-title-main">Buffy coat</span>

The buffy coat is the fraction of an anticoagulated blood sample that contains most of the white blood cells and platelets following centrifugation.

The Cohn process, developed by Edwin J. Cohn, is a series of purification steps with the purpose of extracting albumin from blood plasma. The process is based on the differential solubility of albumin and other plasma proteins based on pH, ethanol concentration, temperature, ionic strength, and protein concentration. Albumin has the highest solubility and lowest isoelectric point of all the major plasma proteins. This makes it the final product to be precipitated, or separated from its solution in a solid form. Albumin was an excellent substitute for human plasma in World War Two. When administered to wounded soldiers or other patients with blood loss, it helped expand the volume of blood and led to speedier recovery. Cohn's method was gentle enough that isolated albumin protein retained its biological activity.

Erythrocytapheresis is an apheresis procedure by which erythrocytes are separated from whole blood. It is an extracorporeal blood separation method whereby whole blood is extracted from a donor or patient, the red blood cells are separated, and the remaining blood is returned to circulation.

Chromatography is a physical method of separation that distributes the components you want to separate between two phases, one stationary, the other moving in a definite direction. Cold ethanol precipitation, developed by Cohn in 1946, manipulates pH, ionic strength, ethanol concentration and temperature to precipitate different protein fractions from plasma. Chromatographic techniques utilise ion exchange, gel filtration and affinity resins to separate proteins. Since the 1980s it has emerged as an effective method of purifying blood components for therapeutic use.

Blood plasma fractionation are the general processes separating the various components of blood plasma, which in turn is a component of blood obtained through blood fractionation. Plasma-derived immunoglobulins are giving a new narrative to healthcare across a wide range of autoimmune inflammatory diseases. This widespread applicability is anticipated to leverage market prospects for plasma fractionation, pegged to witness a noteworthy 7% CAGR. COVID-19 pandemic is expected to generate growth opportunities for the plasma fractionation market.

References

  1. Smalberger C, Nathan M, Rubin DM, Nel M, Kotopoulis S, Carlson CS, Postema M (2022). "Experimental setup for the ultrasonic fractionation of flowing whole blood in a capillary". Current Directions in Biomedical Engineering. 8 (2): 89–92. doi: 10.1515/cdbme-2022-1024 .
  2. Blood Plasma Pooling (from the Bloodbook.com website)
  3. Statement by Dr. Kathryn Zoon, Food and Drug Administration (before the U.S. Congress, July 31, 1997) (via archive.org)