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Whereas precipitation reactions involve soluble antigens,___________ is the visible aggregation of particles caused by combination with specific antibody.
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Agglutination is actually a two-step process, involving ________ or initial binding followed by lattice formation, or formation of large __________.
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Aglutination
| Question | Answer |
|---|---|
| Whereas precipitation reactions involve soluble antigens,___________ is the visible aggregation of particles caused by combination with specific antibody. | agglutination |
| Agglutination is actually a two-step process, involving ________ or initial binding followed by lattice formation, or formation of large __________. | sensitization; aggregates |
| Antibodies that produce such reactions are often called ____________ | agglutinins |
| Types of particles participating in such reactions include erythrocytes, bacterial cells, and inert carriers such as _________particles | latex |
| Each particle must have multiple antigenic or determinant sites, which are _________ to sites on other particles through the formation of antibody ___________. | cross-linked ; bridges or lattices |
| Agglutination, like precipitation, is a two-step process that results in the formation of a ____________. | stable lattice network |
| The first in agglutination reaction involves antigen–antibody combination through ______ antigenic determinants on the particle surface and is often called the __________ step. | single; sensitization |
| The affinity and avidity (discussed in Chapter 8) of an individual antibody determine how much antibody remains _______. | attached |
| IgM with a potential valence of 10 is over 700 times more _________ in agglutination than is IgG with a valence of 2. | efficient |
| The second stage of agglutination, representing the sum of interactions between antibody and multiple antigenic determinants on a particle, is dependent on_____ conditions and the relative __________ of antigen and antibody. | environmental; concentrations |
| Antibody must be able to _________ between cells in such a way that one molecule can bind to a site on each of two different cells. | bridge the gap |
| The surface charge must be controlled for ________, for a visible agglutination reaction, to take place.One means of accomplishing this is by decreasing the buffer’s _______ through the use of low-ionic-strength saline (LISS). | lattice formation;ionic strength |
| The addition of albumin in concentrations of 5 to 30 percent also helps to _____ the surface charge and allows _______ to approach each other more closely. | neutralize; red cells |
| Other techniques that enhance agglutination include increasing the ________, using _______, agitating or _______, and altering the temperature or the pH. | viscosity; enzymes; centrifuging |
| Agglutination reactions can be classified into several distinct categories: ________ | direct, passive, reverse passive, agglutination inhibition, and coagglutination. |
| ______ agglutination occurs when antigens are found naturally on a particle. | Direct |
| One of the best examples of direct agglutination testing involves_______bacterial antigens used to test for the presence of __________ in the patient. | known; unknown antibodies |
| One such example is the Widal test, a rapid screening test to help determine the possibility of _____________. | typhoid fever |
| The antigens used in this procedure include ________ O (somatic) and H (flagellar) antigens. | Salmonella |
| If an agglutination reaction involves red blood cells, then it is called _______________.The best example of this occurs in _________ typing of human red blood cells. | hemagglutination; ABO blood group |
| Positive reactions can be graded to indicate the __________ of the reaction | strength |
| This type of hemagglutination reaction is simple to perform, is relatively _______, and is easy to read. | sensitive |
| A titer that yields semiquantitative results can be performed in test tubes or microtiter plates by making __________ of the antibody. | serial dilutions |
| The reciprocal of the last dilution still exhibiting a visible reaction is the _____, indicating the antibody’s strength. | titer |
| Passive, or indirect, agglutination employs particles that are coated with ________ not normally found on their surfaces. | antigens |
| A variety of ________, including erythrocytes, latex, gelatin, and silicates, are used for this purpose. | particles |
| The use of synthetic beads or particles provides the advantage of consistency, uniformity, and________. Reactions are easy to read visually and give_____ results. | stability; quick |
| ______ particles are inexpensive, are relatively stable, and are not subject to cross-reactivity with other antibodies. | Latex |
| A large number of antibody molecules can be bound to the surface of _______, so the number of antigen binding sites is large.In addition, the large particle size facilitates reading of the test. | latex particles |
| In__________ agglutination, antibody rather than antigen is attached to a carrier particle.This type of testing is often used to detect __________. | reverse passive; microbial antigens |
| Use of __________ has greatly cut down on cross-reactivity, but there is still the possibility of interference or nonspecific agglutination. | monoclonal antibodies |
| Such tests are most often used for organisms that are ________ in the laboratory or for instances when rapid identification will allow treatment to be initiated more promptly. | difficult to grow |
| In all of these reactions, rheumatoid factor will cause a__________ as it reacts with any IgG antibody, so this must be taken into account. | false positive |
| Agglutination __________ reactions are based on competition between particulate and soluble antigens for limited antibody-combining sites, and a _______ agglutination is an indicator of a positive reaction. | inhibition; lack of |
| The Agg ihibition reaction involves haptens that are complexed proteins; the hapten–protein conjugate is then attached to a __________. | carrier particle |
| The patient sample is first reacted with a limited amount of ________ that is specific for the hapten being tested. | reagent antibody |
| Indicator particles that contain the same ________ one wishes to measure in the patient are then added. | hapten |
| If the patient sample has ____________ hapten, the reagent antibody is able to combine with the carrier particles and produce a ________ | no free ; visible agglutination. |
| In this case, however, agglutination is a ________ reaction, indicating that the patient did not have sufficient hapten to inhibit the secondary reaction | negative |
| Hemagglutination inhibition reactions use the same principle, except red blood cells are the ___________. | indicator particles. |
| This type of testing has been used to detect antibodies to certain __________, such as rubella, mumps, measles, influenza, parainfluenza, HBV, herpes virus, respiratory syncytial virus, and adenovirus. | viruses |
| __________ is the name given to systems using bacteria as the inert particles to which antibody is attached. | Coagglutination |
| ___________ is most frequently used, because it has a protein on its outer surface, called _________, which naturally adsorbs the _________ of antibody molecules.The active sites face outward and are capable of reacting with _________ antigen | Staphylococcus aureus; protein A; FC portion;specific |
| These particles exhibit ________ than latex particles and are __________ to changes in ionic strength. | greater stability ; more refractory |
| However, because bacteria are not ________, reactions are often difficult to read. | colored |
| The antihuman globulin test, also known as the _________, is a technique that detects _______ by means of coupling with a second antibody.It remains one of the most widely used procedures in blood banking. | Coombs’ test; nonagglutinating antibody |
| The key component of the test is antibody to ________ that is made in animals or by means of _________ techniques.Such antibody will react with the _______ of the human antibody attached to red blood cells. | human globulin; hybridoma; FC portion |
| Agglutination takes place because the antihuman globulin is able to _______ the distance between cells that IgG alone cannot. | bridge |
| The ___________ test is used to demonstrate in vivo attachment of antibody or complement to an individual’s red blood cells. | direct antiglobulin |
| This test serves as an indicator of autoimmune ________, hemolytic disease of the newborn, sensitization of red blood cells caused by the presence of______, or a ________ reaction. | hemolytic anemia; drugs; transfusion |
| The ________ test, or indirect Coombs’ test, is used to determine the presence of a particular antibody in a patient, or it can be used to type patient _________ for specific blood group antigens. | indirect antiglobulin; red blood cells |
| Washed red blood cells and antibody are allowed to combine at ____, and the cells are then carefully __________ again to remove any unbound antibody. | 37°C; washed |
| When _________ is added, a visible rxn occurs where antibody has been specifically bound.This test is most often used to check for the presence of clinically significant _____ in patient serum when performing compatibility testing for a blood transf. | antihuman globulin; alloantibody |
| Quality Control and Quality AssuranceAlthough agglutination reactions are simple to perform, interpretation must be _______ | carefully |
| Techniques must be ______ as to concentration of antigen, incubation time, temperature, diluent, and the method of reading. | standardized |
| The possibility of _______ and interfering antibody should always be considered. | cross-reactivity |
| Cross-reactivity is caused by the presence of _____ that resemble one another so ________ that antibody formed against one will react with the other. | antigenic determinants; closely |
| Most cross-reactivity can be avoided through the use of __________directed against an antigenic determinant that is unique to a particular antigen. | monoclonal antibody |
| ______ antibody and _________ factor are two interfering antibodies that may produce a false-positive result. | Heterophile;rheumatoid |
| Heterophile antibodies (see Chapter 3) are most often a consideration when red blood cells are used as _______.Other considerations include proper storage of reagents and close attention to expiration dates. | the carrier particle |
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