hook effect


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hook effect

falsely low values on an immunoassay when an overwhelming amount of antigen affects the binding capacity of the added antibody; especially when testing for thyroglobulin in management of thyroid cancer.

hook effect

A curvilinear artefact occasionally seen in the immunoradiometric assay (IRMA) which appears when the hormone being measured is present in very high concentrations. The detector system will not measure the excess, as it will have reached a theoretical limit; the decreased counts bound with the labelled antibody at high hormone levels result in a spuriously decreased result being reported. IRMA should not be used for measuring hormones that may be in high concentrations—hCG, prolactin, or gastrin in clinical samples. The hook effect requires the measurement of two different concentrations to establish linearity.
References in periodicals archive ?
The first of these is the high-dose hook effect. This effect is a very high amount of antigen causing lower detection of antigen by weakening the antigen-antibody binding in an immunoassay system.
We report a rare case of complete molar pregnancy who presented with an enlarged uterus and symptoms related to the compression on adjacent organs, severe anemia despite the absence of vaginal bleeding, and a relatively low serum [beta]-hCG level owing to the "hook effect."
Tg measured by sandwich immunoassay is prone to the hook effect and interference from heterophilic antibodies and Tg autoantibodies (TgAb).
This ELISA kit offers an analytical sensitivity (LLOD) of ~0.04 [micro]g/g and does not exhibit a high-dose hook effect up to 64,800 [micro]g/g.
So why high level of serum beta [beta]-hCG and positive urine pregnancy test is a common finding with rarest exception (hook effect).
Among other benefits associated with the rapid vertical flow technique are the separation of sample and conjugate, which is conducive to better performance, and the "hook effect": in lateral flow, undiluted specimen will overwhelm the internal color conjugate upon reaction, prior to moving toward the reaction zone.
The underlying problem was in the hook effect of the extractor, a part which is located on the right side of the bolt.
After the base model was selected, we developed incrementally more complex models that then included a hook effect and interaction terms between hook and other factors.
The Thyrotest method agreed quite well with the reference method (n = 80) while the Thyrocheck gave extremely high values on 8 samples, suggesting a possible interference or high-dose hook effect.
The capacity of the equipment ensures there is no cross-reactivity with near neighbour strains or household powders; no set up time is required; it does not need expensive readers; decontamination is not necessary; there are no false positives or false negatives and there is no hook effect.
The high dose hook effect is seen, when a crucial limit the analyte
(2,3) This is also called "hook effect" or "prozone phenomenon" can be observed in immunometric sandwich assay.