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Flashcards

Weeks 12-13: Immunoassay Reference Summary

Robert Borden Medicine MLT English 59 cards

Cards in this deck (59)

  1. 1ABTS2,2'-Azino-bis(3-ethylbenzothiazoline-6-sulfonic acid), a colorimetric substrate for horseradish peroxidase that produces a green color
  2. 2AffinityA measure of how tightly the antibody binds to its specific antigen
  3. 3Alexa FluorA family of highly stable fluorophores with various colors, commonly used in
    modern immunoassays
  4. 4Alkaline Phosphatase (AP)Enzyme label used in colorimetric assays, it dephosphorylates substrates, producing a color change
  5. 5Allergenic AntigenProteins that are recognized by the immune system in sensitized individuals who have previously been exposed to the antigen; re-exposure results in an overreactive immune system and allergy symptoms
  6. 6AntibodyA specialized protein produced by the immune system in response to the presence of an antigen, highly specific
  7. 7Antibody SpecificityDictated by the unique shape and chemical structure of the epitope, which allows for the high degree of precision required for immunoassay detection
  8. 8AntigenA substance that can stimulate an immune response, are often the molecules that need to be detected or measured in immunoassays
  9. 9Antigen-Binding Sites (Fab)Highly variable regions located at the ends of the antibody and are composed of portions of both the heavy and light chains
  10. 10AvidityThe overall strength of the binding between an antigen and multiple antibody molecules, considers the sum of interactions between multiple binding sites
  11. 11β-GalactosidaseEnzyme label that produces a colorimetric reaction with specific substrates, often used in enzyme-linked immunosorbent assays (ELISAs)
  12. 12BackgroundThe non-specific signal detected by an immunoassay that does not originate from the target analyte, caused by caused by a variety of factors, such as residual antibodies, impurities in reagents, or environmental factors
  13. 13Capture AntibodyAn antibody designed to bind and immobilize the target analyte (or antigen) onto a solid phase, such as the surface of a microplate or beads and used in ELISA and immunoprecipitation
  14. 14Chemiluminescence Immunoassay (CLIA)A diagnostic method that detects and quantifies specific analytes by measuring light emission produced from a chemiluminescent reaction between an antigen and an antibody
  15. 15Chemiluminescent LabelsVery highly sensitive labels that generate light as a result of a chemical reaction without the need for an external light source; the intensity of the emitted light is directly proportional to the amount of analyte detected and used in chemiluminescent immunoassays (CLIAs), ELISA, and Western Blotting
  16. 16Colorimetric LabelsLabels producing a color change when the antibody-antigen interaction occurs, and the intensity of the color is directly proportional to the amount of analyte present; the labels are often used in ELISA, lateral flow assays, and immunohistochemistry and moderately sensitive
  17. 17Competitive ImmunoassaysThe analyte in the sample competes with a labeled antigen (a version of the analyte that has been tagged with a detectable marker, such as chemiluminescent, fluorescent, or radio-labeled) for binding to a limited number of antibody binding sites, used for therapeutic drug analysis
  18. 18Constant Region (Fc)The part of the antibody that remains the same across all antibodies of the same class (IgG, IgM, IgA, IgD, IgE), does not participate in antigen binding but plays a role in immune system activation by binding with immune cells
  19. 19Cross ReactivityThe phenomenon where an antibody or antigen interacts with substances that are structurally similar to the target analyte but are not the intended analyte, indicative of low specificity
  20. 20Detection AntibodyAntibody is used to bind to the analyte after it has been captured by the capture antibody. It is typically conjugated with a label (e.g., enzyme, fluorophore, or chemiluminescent marker) to allow for the visualization
  21. 21Dynamic RangeThe range of analyte concentrations over which the immunoassay can produce a quantifiable and accurate response; a broad dynamic range ensures that the immunoassay can measure both high and low analyte concentrations which is key in clinical applications
  22. 22Endogenous AntigenForeign molecules that enter the body from external sources, triggering an immune response
  23. 23Enzyme LabelsHighly sensitive enzymes attached to antibodies or antigens; when the enzyme interacts with its specific substrate, it catalyzes a reaction that produces a detectable signal
  24. 24Enzyme-Linked Immunosorbent Assay (ELISA)A technique used to detect and quantify specific antigens or antibodies by utilizing enzyme-linked antibodies and a substrate that produces a measurable signal
  25. 25EpitopesThe specific regions or sites on the antigen that are recognized by antibodies or immune receptors, often amino acids or sugar residues
  26. 26Exogenous AntigenMolecules that are produced internally within the body that are normally recognized as self though may be regarded as foreign in disease states; these include tumor antigens and in autoimmune diseases
  27. 27FluoresceinFluorescent compound that emits green fluorescence when excited by light around 495 nm
  28. 28Fluorescence Polarization Immunoassay (FPIA)A technique that measures the polarization of fluorescence emitted from a fluorescently labeled antigen that competes with an unlabeled target analyte for binding to a specific antibody; the degree of fluorescence polarization is inversely proportional to the amount of free, labeled antigen in the sample
  29. 29Fluorescent LabelsMolecules that emit light when exposed to light of a specific wavelength and attached to antibodies or antigens, highly sensitive
  30. 30HaptenAntigens too small to be recognized by the immune system on their own and require a larger molecule (called a carrier protein) to trigger an immune response
  31. 31Heterogeneous ImmunoassaysSeparation required to distinguish between the bound and free components, helping reduce background noise and improve signal clarity
  32. 32Heterophile AntibodyNon-specific antibodies that are naturally present in some individuals, usually the result of prior exposure to foreign proteins, such as those from vaccines and infections that can cross react with immunoassay antibodies
  33. 33High ConcentrationThe calibration point that ensures the assay is accurate at the upper end of the expected range of analyte concentrations
  34. 34Homogeneous ImmunoassaysNo need for a separation step because the binding reaction occurs in a single phase, detection occurs without the need to separate the bound from the free analyte
  35. 35Hook EffectAn interference that occurs in immunoassays, especially in sandwich-type assays, when the concentration of the analyte is extremely high, leads to falsely low results
  36. 36Horseradish Peroxidase (HRP)An enzyme label that catalyzes the oxidation of substrates, often leading to a color change or chemiluminescence
  37. 37Hybridoma TechnologyTechnique where a single B-cell is fused with a myeloma (cancer) cell to create a hybrid cell, or hybridoma, that can produce an infinite supply of identical antibodies
  38. 38ImmunoassaysDependent on the natural ability of antibodies to bind to specific antigens or vice-versa, allowing for detection of trace amounts of a substance
  39. 39ImmunogenicityThe ability of a substance that contains antigens to cause the body to make an immune response against that substance
  40. 40InterferenceThe distortion of immunoassay results caused by substances other than the target analyte that are present in the sample
  41. 41Low ConcentrationThe calibration point that typically represents the lower limit of quantification, where the analyte concentration is still detectable but low enough that precision may begin to decrease
  42. 42Limit of Detection (LOD)The smallest amount of analyte that can be reliably detected by the immunoassay, but not necessarily quantified, helps determine sensitivity and crucial in low concentration analyses
  43. 43Magnitude of the Calibration CurveThe overall strength or intensity of emitted light during the chemiluminescent reaction, critical in determining the sensitivity of the immunoassay
  44. 44Matrix EffectsThe influence of other components in the sample matrix that can alter the reaction in an immunoassay and affect the measurement of the analyte
  45. 45Microparticle Enzyme Immunoassay (MEIA)A technique that works by using microparticles coated with a specific antibody that binds to the target analyte in a sample; the signal is usually a color change, which can be quantified to determine the concentration of the analyte
  46. 46Mid-ConcentrationThe calibration point that is important for testing the linear range of the assay and ensuring accuracy and precision around the most common concentrations expected in clinical samples
  47. 47Monoclonal AntibodiesAntibodies derived from a single B-cell clone, meaning they recognize only one specific epitope on the antigen, has high specificity and created through hybridoma technology
  48. 48Non-Specific BindingA type of interference that refers to unintended or non-target interactions between assay components
  49. 49Non-Competitive (Sandwich) ImmunoassaysAn assay where a capture antibody is used to capture the analyte and a detection antibody is labeled for detection, with the analyte sandwiched between them; the assay has a direct relationship between analyte concentration and the signal intensity: as the analyte concentration increases, the signal generated by the label increases proportionally
  50. 50Polyclonal AntibodiesAntibodies generated by multiple B-cells, each producing antibodies that recognize and bind to different epitopes on the same antigen, has broad specificity and created by immunizing animals
  51. 51Prozon EffectLack of cross-linking between the Antibody and the Antigen due to antibody excess
  52. 52Radioactive LabelsVery highly sensitive labels that use radioisotopes attached to antibodies or antigens; the radiation emitted by the isotope is measured to determine the concentration of the analyte and used in radioimmunoassays (RIA)
  53. 53RhodamineA fluorescent label that emits red fluorescence and is often used for multicolor detection
  54. 54SensitivityThe ability of an immunoassay to detect small amounts of an analyte, even at low concentrations
  55. 55Signal-to-Noise Ratio (SNR)A measure of the strength of the desired signal compared to the background noise, refers to the clarity of the signal produced
    by the assay
  56. 56Specimen DilutionA common practice when analyte concentration exceeds the upper limit of
    the assay’s calibration curve and dilutingthe specimen helps bring the
    analyte concentration into the measurable range
  57. 57SpecificityThe ability of an immunoassay to accurately detect a particular analyte (target molecule) without cross-reactivity or interference from other similar substances
  58. 58TMB3,3',5,5'-Tetramethylbenzidine, a colorimetric substrate for HRP that produces a blue color, which turns yellow after further oxidation
  59. 59Zero Point (Blank)The point that represents the signal measured from a sample that does not
    contain the analyte of interest

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MLT Medicine Flashcards on Weeks 12-13: Immunoassay Reference Summary, created by Robert Borden on 23/04/2025.
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