A Case With Immunoassay Interferences in the Measurement of Multiple Hormones

Abstract

This report illustrates a rare case of falsely elevated hormone levels due to assay interference caused by heterophile antibodies. We point out the importance of a close collaboration between clinicians and the laboratory to avoid unnecessary clinical investigations as well as inappropriate treatments.

Adrenocortical carcinoma masquerading as Cushing's disease

“…Further, heterophile antibodies may also interfere with ACTH assay measured by the electrochemiluminescence immunoassay method ; however, in such a scenario the ACTH levels are usually very high and polyethylene glycol separation is required for correct estimation. This was not observed in the index case as the ACTH levels were in the normal range 9. In most of the studies on ACTH levels have been carried out in the morning or evening; however, it should be carried out when there is nadir of ACTH between 23:00 and 1:00 hours and ACTH level of >22 pg/mL at midnight has been suggested as a cut-off for ACTH dependency 8…”

False biochemical diagnosis of hyperthyroidism in streptavidin-biotin-based immunoassays: the problem of biotin intake and related interferences

“…Интерференция гетерофильных антител известна в течение нескольких десятилетий. Они могут повлиять на любой иммунохимический тест [19], хотя в большинстве случаев интерференция обнаруживается в «сэндвич»-тестах, вызывая ложноположительный результат [20], в отличие от интерференции с биотином. Чрезвычайно редко сообщалось об ошибочных результатах сразу нескольких исследований на гормоны вследствие интерференции гетерофильных антител [20,21].…”

“…Они могут повлиять на любой иммунохимический тест [19], хотя в большинстве случаев интерференция обнаруживается в «сэндвич»-тестах, вызывая ложноположительный результат [20], в отличие от интерференции с биотином. Чрезвычайно редко сообщалось об ошибочных результатах сразу нескольких исследований на гормоны вследствие интерференции гетерофильных антител [20,21]. Хотя интерференция биотина менее известна, она также вызывает беспокойство, поскольку благодаря ей может быть получен патологический гормональный профиль из-за множественных некорректных результатов, как ложноположительных, так и ложноотрицательных, что может привести к назначению некорректной терапии.…”

False biochemical diagnosis of hyperthyroidism in streptavidin-biotin-based immunoassays: the problem of biotin intake and related interferences

“…The heterophilic antibody interference has been well-known for decades. It can affect any immunoassay [19], although in most cases this interference concerns sandwich assays, provoking a positive error [20], unlike in the biotin interference. In some extremely rare cases, multiple artifacted hormone assays have been reported due to an heterophilic antibody [20,21].…”

“…It can affect any immunoassay [19], although in most cases this interference concerns sandwich assays, provoking a positive error [20], unlike in the biotin interference. In some extremely rare cases, multiple artifacted hormone assays have been reported due to an heterophilic antibody [20,21]. Although less notorious, the biotin artifact is also worrying, as a seemingly coherent hormonal profile can be recorded because multiple, both positive and negative erroneous results are generated; this may lead to inappropriate therapy.…”