How do Heterophile antibodies interfere with immunoassays?
How do Heterophile antibodies interfere with immunoassays?
Heterophile antibodies interfere with immunoassays by a non-competitive mechanism. Heterophiles can bind to the conjugate, enzyme, or other parts of the detection system in reagent-limited assays, mainly of the non-RIA type, and cause interference in assays for steroid hormones, thyroid function tests, and digoxin.
What are Heterophile antibodies?
Heterophile antibodies are antibodies produced against poorly defined antigens. These are generally weak antibodies with multispecific activities. Human anti-animal antibodies that develop as a result of treatments with animal immunoglobulins are antibodies with strong avidities, produced against well-defined antigens.
Which of the following factors may interfere with the results of immunoassays?
Factors that affect an enzyme immunoassay were reviewed from the practical point for clinical laboratory uses: these include prozone effect or hook effect, affinity and avidity, cross-reactivity and specificity of the antibody, and other non-specific factors such as pH, temperature, rheumatoid factor, complement.
What is an immunoassay interference?
Substances that alter the measurable concentration of the analyte or alter antibody binding can potentially result in immunoassay interference. Interference in immunoassay may lead to the misinterpretation of a patient’s results by the laboratory and the wrong course of treatment being given by the physician.
What is heterophile IgM?
Heterophile antibodies are IgM antibodies with affinity for sheep and horse red blood cells. They appear during the first week of infectious mononucleosis symptoms, 3–4 weeks after infection and return to undetectable levels 3 to 6 months after infection.
Why is it important to control pH in immunoassays?
Importance of pH Measurement ensure unexpected phenomena do not occur. When scaling up from the lab scale to the production scale, issues such as altered chemical reaction equilibrium, clumping together of coarser chemicals, and other unexpected results can occur.
What does Heterophile antibody test for?
The heterophile test is the most common and specific test to confirm the diagnosis of infectious mononucleosis. Paul and Bunnell first described the presence of heterophile antibody in patients with infectious mononucleosis in 1932.
What is heterophile specificity?
Heterophile antibodies are low-affinity IgM antibodies with broad specificity for predominantly carbohydrate antigens that can react with molecules found on the surface of a number of nonhuman erythrocytes (hence heterophile = other loving).
What is cross reactivity in immunoassays?
Cross-reactivity is the ability of the antibody to bind other structures than the target analyte. These structures have often a high similarity or homology to the analyte. If the used antibodies have a high affinity, these problems can be avoided.
How do you get rid of Heterophile antibodies?
Blocking heterophile antibody interference can be achieved by removal of immunoglobulins from a sample (such as with PEG), by modifying antibodies which may be present in a sample or by using buffers to reduce interference.
Are heterophile antibodies IGG or IgM?
What is the mechanical basis of all immunoassays?
Immunoassays rely on the inherent ability of an antibody to bind to the specific structure of a molecule. Antibodies are proteins generated by animals in response to the invasion of a foreign molecule (antigen) into the body.
