The hook effect occurs due to oversaturation of the assay, resulting in falsely low laboratory values[^1].
Neurosurgical relevance
This can occur, for example, with prolactin levels during the evaluation of a prolactinoma. Therefore, multiple dilution series should be performed in the laboratory when a Prolactinoma is suspected. This is particularly relevant in cases of large space-occupying lesions of the Pituitary gland and clinical symptoms of hyperprolactinemia.