agglutination Flashcards
false positive or false negative
- Reagent Failure
- Improper washing
- Failure to add AHG
- Improper centrifugation
- Serum/Cell ratio is too low
- Delayed washing
false negative reaction
P.A. or R.P.A.
- carrier: LATEX
- component/reagent attached: ANTIBODY
- detects patient’s: ANTIGEN
reverse passive
- Non visiblereaction, first union of Ag-Ab
- ELISA, RIA, IFA
- MOST SENSITIVE
primary Ag-Ab reaction
AHG
Anti C3d or Anti-IgG only Prepared by Monoclonal antibody (mice)
monospecific AHG
- Phagocytosis, Opsonization, chemotaxis
- In vivo Ag-Ab reaction
Tertiary Ag-Ab reaction
Involves measurement of the number of residual non-agglutinating particles in the specimen. These are counted by means of a laser beam in an optical particle counter similar to one that is designed to count blood cells
PACIA (particle counting immunoassay)
- A reaction in which carrier particles coated with antibody clump together because of a combination with antigen
- S. aureus
- S. pyogenes, S. agalactiae
- Neisseria spp., Leptospira
reverse passive agglutination
- Added to Negative AHG test to validate the negative reaction
- Lack of agglutination invalidates the results
O check cell
Forces involved in Antigen-Antibody Binding:
- Electrostatic Forces (Ionic Bonds)
- Van der Waals Forces (London Dispersion Forces)
- Hydrogen Binding
- Hydrophobic Binding
agglutination
potentiator
enhancement
- “in vitro sensitization”
- Crossmatching Test
- Antibody Detection
- Antibody Identification
- Red Cell Antigen Phenotyping: Du Testing
indirect antiglobulin tests
- Sum of all attractive forces between an antigen and an antibody
- the strength with which a multivalent antibody binds a multivalent antigen, and it is a measure of the overall STABILITY of an antigen–antibody complex
avidity
agglutination
The antibody attaches to the antigen on the red cell membrane
sensitization
- is the initial force of attraction that exists between a single Fab site (paratope) on an antibody molecule and a single epitope or determinant site on the corresponding antigen.
- The strength of attraction/interaction between an individual antigen and antibody molecule.
- WEAK BONDS
affinity
After addition of O Check Cell, Agglutination indicates:
1. (?)
2. (?)
- AHG was added
- AHG was not neutralized
AHG
Anti-C3d, Anti-IgG Prepared by Conventional Technique (rabbits)
polyspecific AHG
- A systems using bacteria as the inert particles to which antibody is
attached. - Staphylococcus aureus is most frequently used (Protein A).
- Particles exhibit greater stability than latex particles and are more refractory to changes in ionic strength.
- reactions are often difficult to read.
- (?) reagents have been used in identification of Streptococci, Neisseria meningitidis, Neisseria gonorrhoeae, Vibrio cholera 0139, and Haemophilus influenzae
coagglutination
- A reaction in which particles coated (Latex, RBC, Gelatin, Silica) with antigens not normally found on their surfaces clump together because of combination with antibody
- ANA, RF, Group A Streptococcus
- CMV. HIV, VZV
passive agglutination
- Ability of antibodies to Clump Cells (Gruber & Durham, 1896).
- The process by which particulate antigens such as cells aggregate to form large complexes when specific antibody is present.
- PARTICULATE ANTIGEN + SOLUBLE ANTIBODY → LARGE COMPLEX
agglutination
- in vivo sensitization
- Investigation of HDN
- Investigation of HTR
- Diagnosis of Autoimmune Hemolytic Anemia
- Diagnosis of Drug Induced Hemolytic Anemia
- Penicillin (Drug Adsorption), Cephalosporin (Membrane Modification), Rifampin, Stibophen, Phenacetin (Immune Complex), Methyldopa, Mefenamic Acid (Autoantibody Production)
direct antiglobulin tests
- Reducing (?) of medium facilitates interaction of ab with ag
ionic strength
- visible reaction
- Precipitation, Agglutination, Neutralization, complement Fixation
- LESS SENSITIVE
secondary Ag-Ab reaction
Establishment of cross-links between sensitized particles and antibodies ~ agglutination
lattice formation
- An antigen–antibody reaction that results in the clumping of red blood cells.
- Base on the Sedimentation Pattern
- ABO slide typing
- virus hemmaglutination: influenza, mumps
- DAT/IAT
hemmaglutination
- An agglutination reaction based on competition between antigen-coated particles and soluble patient antigensfor a limited number of antibody combining sites.
- Detection of illicit drugs (Cocaine, Heroin)
agglutination inhibition
- A test for detecting antibodies to certain viruses, based on lack of agglutination as a result of antibody neutralizing the virus
- Detects antibody to Rubella, RSV, Influenza, Mumps, Measles, Adenovirus
hemmaglutination inhibition
- An antigen–antibody reaction that occurs when antigens are naturally found on a particle
- widal testing
- somatic “O”
- flagellar “H”
direct agglutination
Clinically significant abs react best at (?).
37°C
- Study of non-cellular portion of the blood.
- In vitro study of Antigen-Antibody reaction.
- A medical science dealing with blood serum especially in regards to its reaction and properties.
serology
- Optimum serum-to-cell ratio is (?).
- Usually (?) drops serum to (?) drop of 2%–5% RBCs.
- Follow manufacturer’s directions.
- Incorrect ratio will likely to lead to (?) & (?)
- 40:1
- 2
- 1
- pro-zone
- post-zone
- Effective way to enhance
agglutination reactions. - one of the most efficient methods used in blood banking.
centrifugation
P.A or R.P.A
- carrier: LATEX
- component/reagent attached: ANTIGEN
- detects patient’s: ANTIBODY
passive/indirect agglutination
Most abs react at pH (?)
6.5–7.5
agglutination
Sensitized RBC’s come close together by forming bridges created by antibody
lattice formation
false positive or false negative
- Contamination of Reagent
- Over centrifugation
- Strong Agglutinins
- Over incubation with enzyme-treated cell
- Improper used of enhancement reagent
- Saline stored in glass or metal container
false positive
