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 high dose hook effect is seen, when a crucial limit the analyte
04 [micro]g/g and does not exhibit a high-dose hook effect up to 64,800 [micro]g/g.
3) Therefore, it is possible that if the actual serum beta-[beta]-hCG is extremely high, the reported serum [beta]-hCG may be spuriously underestimated due to the hook effect.
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.
On the basis of the descriptions in the MAUDE report, false negatives were subdivided by potential cause unknown, likely hCG[beta]cf hook effect, and likely limit of detection.
This hook effect can be overcome simply by dilution method if suspicion is high.
9) The hook effect can cause very low hCG results or false-negative results when an extremely high hCG concentration is present due to the saturation of all antibody-binding sites on both the capture and signaling antibodies, permitting few or no complex formation.
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.