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 endogenous antibodies?
The 3 types of endogenous antibodies known to cause interferences in immunoassays are heterophile, antianimal, and autoantibodies. Heterophile antibodies are produced without exposure to specific immunogens and are thus considered to be naturally occurring.
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.
What is antibody interference?
Interfering, endogenous substances that are natural, polyreactive antibodies or autoantibodies (heterophiles), or human anti-animal antibodies together with other unsuspected binding proteins that are unique to the individual, can interfere with the reaction between analyte and reagent antibodies in immunoassay.
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 is an endogenous source?
Endogenous sources include errors of metabolism that lead to large accumulations of elements such as copper or iron, which are normally only found in trace quantities.
What is a MAB drug?
Monoclonal antibodies (MABs) are a type of targeted drug therapy. These drugs recognise and find specific proteins on cancer cells. There are many different MABs to treat cancer. They work in different ways to kill the cancer cell or stop it from growing.
How is antibody cross reactivity calculated?
Percent cross-reactivity was calculated by dividing the calculated concentration of a particular antigen run with a particular matched pair by the calculated concentration of the antigen with its intended matched pair.
What is cross reactivity in Western blot?
Cross-reactivity (also called off-target or non-specific binding) occurs when the antibody recognizes other sample proteins with epitopes (the portion of an antigen recognized by an antibody) similar to the target protein.
What is analytical interference?
Analytical and drug interferences. An analytical interference is any effect of a substance that is not the analyte to be determined. The knowledge that drugs may cause falsely elevated, normal and lower values in clinical patient material is very often ignored or not known.
What is the role of heterophile antibodies?
Heterophile antibodies are antibodies induced by external antigens (heterophile antigens). Some cross-react with self-antigens. For example, in rheumatic fever, antibodies against group A streptococcal cell walls can also react with (and thus damage) human heart tissues. These are considered heterophile antibodies.
How are endogenous antibodies related to immunoassays?
Immunoassays are subject to other types of interference. Antigen-antibody interactions are the basis of immunoassays, and compounds or conditions that alter these interactions can interfere with measurement. Endogenous antibodies may bind to, bridge, or block the binding sites on capture and signal antibodies (Figure 1).
What kind of interference can be found in immunoassays?
The three main groups of endogenous antibodies known to cause interference in immunoassays are heterophile, anti-animal and autoantibodies. Endogenous antibodies may bind to, or bridge, or block the binding sites on capture and signal antibodies generating incorrect results.
What is the CLSI guideline for endogenous antibody interference?
The Clinical and Laboratory Standards Institute (CLSI) document, “Immunoassay Interference by Endogenous Antibodies; Approved Guideline” 19 states that it is the responsibility of the clinical laboratory to: Ensure the personnel performing the assay have the required knowledge of endogenous antibody interference.
How are 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.