Precipitation and Agglutination Flashcards

1
Q

Measure of turbidity or cloudiness in a solution

A

Turbidimetry.

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2
Q

Principle of turbidimetry

A

Measures reduction in light intensity due to reflection, absorption, or scatter.

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3
Q

Unit of measurement in turbidimetry

A

Absorbance unit; ratio of incident light to transmitted light.

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4
Q

Principle of nephelometry

A

Measures light scattered at a specific angle.

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5
Q

Information derived from light scattering in nephelometry

A

Indicates solution’s concentration.

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6
Q

Concentration units in nephelometry

A

Milligrams per deciliter (mg/dL) or international units per milliliter (IU/mL).

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7
Q

Type of precipitation in a solid medium

A

Immunodiffusion.

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8
Q

Advantage of passive immunodiffusion

A

No electrical current, cheap, simple.

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9
Q

Disadvantage of passive immunodiffusion

A

Longer turnaround time (TAT).

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10
Q

Factors affecting rate of diffusion in immunodiffusion

A

Particle size, temperature, gel viscosity, hydration.

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11
Q

End product of Single Diffusion, Single Dimension (Oudin Test)- semiquantitative

A

Precipitin line.

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12
Q

Interpretation of line thickness in Single Diffusion, Single Dimension

A

Thicker line indicates higher antigen concentration.

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13
Q

Result of Single Diffusion, Double Dimension (Radial Immunodiffusion)

A

Precipitin ring.

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14
Q

Relationship between diameter and concentration in Radial Immunodiffusion

A

Diameter is directly proportional to concentration.

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15
Q

Method used in Radial Immunodiffusion for quantitative measurement

A

Fahey and McKelvey method (Kinetic Diffusion).

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16
Q

Time and measurement principle in Fahey and McKelvey method

A

19 hrs; diameter is proportional to log concentration.

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17
Q

Method used in Radial Immunodiffusion for end-point measurement

A

Mancini method.

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18
Q

Time for IgG and IgM in Mancini method

A

IgG = 24 hrs, IgM = 50-72 hrs.

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19
Q

Classification of diffusion in Double Diffusion, Double Dimension

A

Qualitative.

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20
Q

Diffusion directions in Double Diffusion, Double Dimension

A

Both horizontal and vertical through semisolid medium.

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21
Q

Result of identical epitopes in Double Diffusion, Double Dimension

A

Arc formation (serological identity).

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22
Q

Result of non-identical epitopes in Double Diffusion, Double Dimension

A

Crossed lines (non-identity).

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23
Q

Key characteristic of antigen in passive immunodiffusion

A

Soluble.

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24
Q

Technique used to separate molecules using electrical current

A

Electrophoresis.

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25
Q

Effect of direct current in electrophoresis

A

Forces antigen, antibody, or both to migrate.

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26
Q

Result of antigen-antibody migration in electrophoresis

A

Distinct precipitin bands form.

27
Q

Disadvantage of electrophoresis

A

Expensive and complex.

28
Q

Type of electrophoresis in Rocket electrophoresis (Laurell Technique)

A

One-dimensional electroimmunodiffusion.

29
Q

Combination technique used in Rocket electrophoresis

A

RID + electrophoresis.

30
Q

Relationship between antigen migration and concentration in Rocket electrophoresis

A

Distance of migration and precipitation is directly proportional to antigen concentration.

31
Q

Interpretation of distance in Rocket electrophoresis

A

Distance from the starting well to the front of the rocket-shaped arc correlates with antigen concentration.

32
Q

Procedure in Immunoelectrophoresis (IEP)

A

Double diffusion + electrophoresis.

33
Q

Procedure in IEP for separating proteins

A

Serum electrophoresed, and a trough is cut parallel to the separation line.

34
Q

Disadvantage of Immunoelectrophoresis (IEP)

A

Difficult interpretation.

35
Q

Difference between Immunofixation Electrophoresis and IEP

A

Immunofixation Electrophoresis: applied directly to the gel surface: quicker immunodiffusion and higher resolution.

36
Q

Use of Immunofixation Electrophoresis

A

Identify and characterize serum/urine proteins.

37
Q

Key feature of Immunofixation Electrophoresis

A

Highly sensitive and specific; identifies monoclonal proteins.

38
Q

Effect of hypogammaglobulinemias in Immunofixation Electrophoresis

A

Faintly staining bands.

39
Q

Effect of polyclonal hypergammaglobulinemias in Immunofixation Electrophoresis

A

Darkly staining bands in the gamma region.

40
Q

Result of monoclonal antibody presence in Immunofixation Electrophoresis

A

Dark, narrow bands in a specific lane.

41
Q

Type of test in Counter Immunoelectrophoresis (CIE)

A

Qualitative.

42
Q

Procedure in Counter Immunoelectrophoresis (CIE)

A

Ag and Ab are placed in wells opposite each other; Ag migrates to anode, Ab to cathode.

43
Q

Result of Ag-Ab interaction in CIE

A

Precipitin line forms where Ag and Ab meet.

44
Q

Use of Counter Immunoelectrophoresis (CIE)

A

Detect bacterial Ags in fluids for rapid response.

45
Q

Year when Gruber and Durham described agglutination reactions

A

1896

46
Q

Process of agglutination reactions

A

Particulate antigen aggregates to form larger complexes in the presence of specific antibody.

47
Q

Term for antibodies that cause agglutination

A

Agglutinins.

48
Q

Two steps in agglutination reactions

A

Sensitization (no clumping) and lattice formation (visible agglutination).

49
Q

Type of agglutination where antigens are naturally present on particles

A

Direct agglutination.

50
Q

Examples of direct agglutination tests

A

Blood typing, Kauffman and White serotyping, Widal test, Weil-Felix, Cold agglutinin test.

51
Q

Pocess where soluble antibody (agglutinin) forms a lattice with an insoluble particulate or cellular antigen.

A

Agglutination

52
Q

Reaction where soluble antigen combines with soluble antibody to produce visible insoluble complexes.

A

Precipitation

53
Q

A technique where antigen is attached to a particulate carrier, detecting antibodies to viruses such as rotavirus, rubella, HBV, HIV.

A

Passive Agglutination

54
Q

A technique where antibodies are attached to particulate carriers with active sites facing outward, used to detect pathogens like Group B Streptococcus.

A

Reverse Passive Agglutination

55
Q

A process where antibodies are bound to a particle (e.g., bacterium) to enhance the visibility of agglutination.

A

Co-agglutination

56
Q

A test where the absence of agglutination indicates a positive reaction, used to detect secretor status and viral antibodies.

A

Agglutination Inhibition

57
Q

A technique that measures non-agglutinating particles by counting them with an optical particle counter, applied in Nephelometry.

A

Particle-Counting Immunoassay (PACIA)

58
Q

A specific type of precipitation that occurs over a narrow range of antigen concentrations and involves fine particles clumping together in a positive reaction.

A

Flocculation

59
Q

Examples of tests using flocculation.

A

Nontreponemal tests: VDRL and RPR.

60
Q

A test measuring the ability of a patient’s antibody to neutralize infectivity and protect cells from infection.

A

Neutralization

61
Q

Types of neutralization tests.

A

Toxin Neutralization (Schick test, Dick Test, ASO Titration) and Virus Neutralization.

62
Q

Characteristic of precipitation and agglutination assays.

A

Unlabelled assays; no marker label is needed to detect the reaction.

63
Q

Limitation of precipitation and agglutination assays.

A

Relatively insensitive, requiring high antigen concentration to visualize the reaction.