Column Agglutination Technology (CAT) in Blood Bank Research Paper

Serology

Serology is a term utilized in study of fluids of the body as well as blood serum. It refers to scientific study of blood. In some cases, especially in practice, it is commonly employed to mean investigative identification of serum antibodies. More often, the antigen results from infections and introduction of foreign proteins, among others. The latter may occur when one experiences a mismatched transfusion of blood. On the other hand, the former comes because of reaction to microorganisms. Therefore, serology forms an integral part of diagnosis, especially when illnesses such as rheumatic diseases are involved. In addition, serology is quite significant in establishing an individual’s blood type. Consequently, it can be utilized in identifying patients with definite immune deficiencies, which are connected with absence of antibodies. These may include among others, X-linked agammaglobulinemia. In such cases, test results are usually negative. Over the years, various serological techniques have been developed and this depends on the kind of antibodies studied. They include ELISA, complement fixation, and precipitation, among others. In recent times, serological tests have been utilized in forensic science as well as in bodily fluids such as saliva, and semen, among others. These fluids usually portray similar properties to serumⁱ.

Blood Bank

Blood bank refers to storage of blood and its components. The storage usually occurs after blood donations, which are aimed at assisting those who need transfusion. Donated blood is usually stored for future use. Blood transfusion involves several processes. These include transportation, storage, and testing, among other related tasks. In practice, blood bank refers to a division in laboratory (Hospital Lab.) where blood storage, testing and in some cases, donation processing, is done. Services of a blood bank usually depend on its capabilities and facilities. For instance, some blood banks do not offer donation-processing services. However, it is quite important to note that most blood banks perform identification of blood types to ensure compatibility. This is mainly because complications that may result after blood transfusion mismatch are quite severe. In addition, blood banks perform disease tests and treatments for enhanced quality. Past experiences in United States hospitals have shown that the cost of dealing with post transfusion complications are way beyond total cost of buying, testing, and/or treating as well as transfusion. In most cases, volunteers donate blood, even though at times some are paid. However, blood-manufacturing companies usually pay for blood plasma from donorsⁱⁱ.

In the United States, blood is categorized as either whole (WB) or in components such as RBC cells (RBC), among others. The former component can be stored for 35 days while the latter for up to 42 days when kept at between 1 and 6 Celsius. In addition, RBC can be stored for about 10 years when frozen at -65 Celsius. Blood plasma can be made into many different frozen components depending on its need. Blood banks were first established in 1915 at Mount Sinai Hospital (New York). During this period, sodium citrate was used as an anticoagulant. These changes led to indirect transfusion procedure. Storage of blood improved as containers could be used. This paved the way for blood depots. Use of blood banks started in 1930s as blood donation centered expanded throughout the world. Interestingly, establishment of blood bank in United States stated later in World War II. This development was credited to Oswald Robertson, who initiated the first depot in United States. Further developments came through Karl Landsteiner between 1939 and 1940 during which he established Rh blood group system. In addition, introduction of acid-citrate-dextrose (ACD) solution allowed for longer storage of blood. Moreover, introduction of plastic bags that were durable replaced the breakable bottles (glass), which were formerly used. Since then, several advancements that include technological development have improved blood storage, testing and treatment as well as transfusionⁱⁱⁱ.

Development of serological techniques

Serology refers to scientific study of blood serum and bodily fluids. The term is at times used to mean investigative identification of serum antibodies. In essence, serology forms an integral part of diagnosis, especially when illnesses such as rheumatic diseases are involved. In addition, serology is quite significant in establishing an individual’s blood type. Consequently, serology can be utilized in identifying patients with definite immune deficiencies, which are connected with absence of antibodies. These may include among others, X-linked agammaglobulinemia. Body immune system has the capacity to manufacture antibodies in response to entrance of foreign invaders. Each antibody is associated with an antigen for destruction by immune system of the body. Serology therefore refers to tests and techniques associated with antibodies and corresponding antigen in test tubes (vitro). Serological techniques have been utilized in determining blood types. Over the years, various serological techniques have been developed and this depends on the kind of antibodies studied. These include ELISA, complement fixation, and precipitation, among others. In recent times, serological tests have been utilized in forensic science as well as in bodily fluids such as saliva, and semen, among others. These fluids usually portray similar properties to serum. The main serological techniques include ELISA, agglutination, Immunoblotting and Immunoprecipitation^iv.

ELISA

Elisa refers to Enzyme-Linked Immunosorbent Assays. There are utilized for various applications. ELISA employs double-sandwich method in its tests. Here, wells in the plate are coated with test antigen as well as the antibody. Antigen that sticks to the corresponding antibody is said to have matched, while that which is washed off does not, is said mismatch. The next step involves addition of modified antibody (tagged with a catalyst, for example an enzyme). Again, the antibody sticks or is washed off depending on presence of a matching antigen. Finally, chemical is added to the enzyme, if its color changes then antigen is said to be present^v.

Agglutination

Molecules of antibody have a Y like shape. The two pointed ends are usually sticky such that if it finds a matching antigen, it binds. One antibody binds to two antigens. However, when there are many antigens then they can be cross-linked to form an immune complex (clump). The immune complex formed is visible. This makes it easy to determine presence of antigen in a given sample. Other serological techniques include Immunoblotting and Immunoprecipitation among others.

Column agglutination technology (CAT)

This technology is also referred to as BioVue CAT micro-column assay. It contains a maximum of 6-column cassette where each column contains a mixture of 50 micro litres of BLISS and 10 micro litres of RBCs suspensions. The next step is to dispense diluted samples in triplicates of 40 micro litres each in the corresponding columns. The cassettes then goes through a process whereby they are incubated for about 10 minutes in Ortho BioVue heat block then spinned down for 5 minutes in a centrifuge. After the process of centrifugation is done with, then examination of cards for agglutination follows. The resulting outcome should indicate a separation of agglutinated RBC cells from unagglutinated cells. As a result, agglutinated RBC cells are trapped overhead column glass beads while unagglutinated red cells pass through glass beads to form a pellet at the lowermost. The last step in this process is a significant titer, which is a dilution that is added to bead columns. If the resulting solution is positive then there is agglutination of RBC cells. On the other hand, if a negative result is seen, when all the RBC cells pass through the column glass beads, this results in formation of a smooth button at the bottom of bead column^vi. This type of agglutination technology has several merits includes

1. It supports a small sample size
2. Has a variation of volume delivery
3. A repeat test of this technology shows great uniformity between them.
4. It does not have a cell-washing step
5. There is decreased dependence on the technique

Column agglutination technology (CAT) in blood bank

Recent technologies used in blood banks revolve around use of column agglutination technology for serological testing. The technique is based on a principle of gel filtration used for separating RBC cells from human blood. The principle of gel centrifugation was later modified as a serological tool by incorporating use of Sephadex G100 superfine or Sephadex G200. The main aim of this technology as given by Lapierre et al is to standardize the agglutination reactions of the RBC cells and enable efficient reading. The columns are made up of micro tubes, which contain a dextran gel matrix. A dispensation is done to these columns by placing RBC cells and serum. Centrifugation is then done under controlled parameters. The dextran gel matrix acts as a sieve and it may be neutral or contain antibodies such as Anti-A, anti-D and many others. This technology allows for visibility of reactions along with ease in grading. It does not require washing of RBC cells since centrifugation allows cell separation from suspension medium as they move through micro-tubes. Column agglutination technology alleviates the need for use of pre-sensitized control cells to check negative reactions. Gel techniques reactions are said to be stable for at least 48 hours and enable photocopying of the process hence more reliable in cases where reference is needed in future use^vii.

Comparison of Ortho and Lateral Grifolds CAT technology

Several types of Column agglutination technologies are employed in serology. These include among others, Ortho and Grifols CAT technologies. The latter is manufactured by Grifols diagnostics while the former is made by Ortho (clinical) diagnostics.

Ortho CAT technology

Ortho is widely used in the world market due to its unique features, which overrides standard techniques. They exist in different brands. The most notable of which is BioVue brand, which has served different parts of the world for over a decade. This is mainly because it standardizes compatibility tests on blood as well as blood typing. It does this in a 6-microcolumn which is usually preloaded with glass beads, reagents and/ or diluent. Test RBC are usually placed overhead the above-mentioned column. This is carried out whether the RBS cells are with serum or not. After centrifugation has taken place, RBC cells that have been agglutinated are forced to pass through the bead column. This is where they are trapped. On the other hand, unagglutinated RBC cells form discrete pellets below the column. The technique offers several advantages namely, objectivity, ease for automation, simplicity (easy to use), increased productivity, enhanced sensitivity, and standardized procedures. Moreover, the cassettes can be utilized manually for smalls scale testing. However, large scale testing requires automation platform, which is also available^viii.

Lateral Grifols CAT technology

These are made by Lateral Grifols diagnostics. They are Gel products and are usually distributed in vitro diagnostics. This makes it reliable and of high quality for efficacy. Lateral Grifols is designed in eight well configurations, which allows for utilization of COMBITHERM technology^ix. The technology is credited with reliability, among other advantages. These include its ability to save time, reduce on cost, provide a reverse and forward groups as well as RhD types. Moreover, the technology provides 3-cell screen for antibodies on a single card. The technology also helps in environmental conservation as it minimizes greenhouse emissions. In comparison with Ortho, Lateral Grifol saves 30% more energy and 90% of water, through its recycling system. On the other hand, Ortho CAT technology is easy to use, which attributes to increased productivity. It also boasts of enhanced sensitivity, and standardized procedures^x.

Reference List

Brennan J. Serological Techniques. 2011. Web.

Brown M, Crim P. IMMUNOHEMATOLOGY: Organizing the Antibody Identification Process. Clin Lab Sci 2007; 20(2):122-126.

Coombs RA. Historical Note: Past, Present and Future of the Antiglobulin Test. Vox Sanguinis 1998; 74:64-73.

Ibrahim HE. Evaluation of BioVue Column Agglutination Technology for quality control purpose of therapeutic anti-Rh immunoglobulin preparations. Journal of King Saud University 2010; 22: 209–212.

Knight RC, De Silva M. Blood transfusion: New technologies for red-cell serology. Blood Reviews 1996; 10: 101-110.

Lateral Grifols. Diagnostics. 2011. Web.

Marik PE, Corwin HL. Efficacy of red blood cell transfusion in the critically ill: a systematic review of the literature. Crit Care Med 2008; 36:2667-2674.

Moulds G. Antibody identification. Transfusion and Apheresis Science 2009; 40: 195–197.

Ortho-Clinical Diagnostics. Immunohematology: ORTHO BioVue. 2011. Web.

Shander A, Hofmann A, Gombotz H, Theusinger OM, Spahn DR. Estimating the cost of blood: past, present, and future directions. Best Pract Res Clin Anaesthesiol 2007; 21:271-289.

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