Biotin interference in clinical immunoassays

S obzirom na činjenicu da se biotin sve više koristi u multivitaminskim dodatcima, preparatima na osnovi biotina za kožu, kosu i nokte te kao lijek za liječenje progresivne multiple skleroze djelatnici medicinskobiokemijskih laboratorija i liječnici trebaju biti svjesni da biotin može utjecati na rezultate u imunokemijskim analizama koje rabe biotin i interakciju biotin – streptavidin u svojem formatu. Biotin utječe na rezultate u imunokemijskim analizama na dva načina: u kompetitivnom formatu testa prouzrokuje lažno pozitivne rezultate, a u sendvič-formatu testa prouzrokuje lažno snižene rezultate. Cilj je ovoga rada bio istražiti utjecaj biotina na pet analita (vitamin D, CEA, CA 19-9, AFP i vitamin B12 ) kad se uzima u dozi od 5 mg. Istraživanje je osmišljeno tako da se dva puta mjere koncentracije analita u serumu (prije uzimanja biotina i tri sata nakon uzimanja biotina). U istraživanju je sudjelovalo 12 ispitanika (šest muških i šest ženskih) i koncentracije biotina određivane su na imunokemijskom analizatoru Cobas e601 koristeći se imunokemijskom metodom elektrokemiluminscencije (ECLIA). Istraživanjem je dokazano da biotin u dozi od 5 mg ne interferira niti u jednom od 12 ispitanika kod CEA, CA 19-9, AFP i vitamina B12, a kod vitamina D interferira u jednom od 12 ispitanika. Ako se biotin uzima u puno većim dozama od 5 mg (terapijske doze za multiplu sklerozu iznose od 100 do 300 mg) on će tada interferirati kod svih analita. Da bi se izbjegle interferencije biotina klinički laboratoriji rabe četiri načina. To su korištenje platformom za ispitivanje koja se ne koristi biotinom u osmišljavanju ispitivanja, serijsko razrjeđivanje uzorka, čekanje dovoljno vremena da se biotin ukloni iz tijela i predtretman uzorka mikročesticama obloženima streptavidinom za uklanjanje biotina prisutnog u uzorcima. Djelatnici kliničkih laboratorija trebaju biti oprezni kod interpretacije rezultata i trebaju poučiti pacijente kako se pGiven the fact that biotin is increasingly used in multivitamin supplements, biotin-based skin, hair and nail products, as well as a medication for treatment of progressive multiple sclerosis, medical biochemistry laboratory professionals and physicians should be aware that biotin can affect results in immunochemical analyses that use biotin and the streptavidin-biotin interaction in their platform. Biotin affects the results in immunochemical analysis in two ways: in competitive tests it causes false positive results, and in sandwich tests it causes false low results. The aim of this paper was to examine the impact of biotin on five analytes (vitamin D, CEA, CA 19- 9, AFP and vitamin B12) when administered at a dose of 5 mg. The research was designed in such a way to measure the concentrations of analytes in serum two times (before taking biotin and three hours after taking biotin). Twelve subjects participated in the research (six male and six female) and biotin concentrations were determined with the Cobas e601 immunoassay analyser using the electrochemiluminescence immunoassay (ECLIA) method. The investigation showed that 5 mg of biotin did not interfere in any of twelve subjects with CEA, CA 19-9, AFP and B12, and in terms of vitamin D, it interfered with one out of twelve subjects. If biotin is taken at doses much higher than 5 mg (therapeutic doses for multiple sclerosis range from 100 to 300 mg), it will interfere with all analytes. There are four methods that clinical laboratories use in order to avoid biotin interference. These are the use of a test platform that does not use biotin in the design of the assay, serial dilution of the sample, waiting long enough for the biotin to be removed from the body and pre-treatment of samples with streptavidin-coated microparticles for the removal of biotin present in the samples. Clinical laboratory professionals should be careful when interpreting results and should educate patients on how to prepare for immunochemical analysis if they take biotin and thus minimise errors in lab results