Turkish Journal of Biochemistry – Türk Biyokimya Dergisi 2016; 41(2): 127–130 Clinical Biochemistry Case Report – 57689 Özlem Çakır Madenci*, Nihal Yücel, Lale Köroğlu Dağdelen, Yusuf Temel, Aycan Bölük, Asuman Orçun Kaptanağası A paraprotein interference and its management in clinical laboratory Bir paraprotein interferansı vakasının klinik laboratuvarda yönetimi DOI 10.1515/tjb-2016-0020 Received June 17, 2015; accepted January 15, 2016 Abstract: In the present study we describe a patient who has interference due to paraproteinemia in her labaratory results. In a patient with a total protein concentration of 10.8 g/dL, a direct bilirubin result higher than total was detected. She also had discordant results in her whole blood count parameters. Further investigation was per- formed on this patient. Presence of any cold agglutinin and cryoglobulin was tested and excluded first. After 2-mer- captoethanol (2-ME) treatment, patient was idendified as Ig-M Kappa monoclonal gammapathy on immunofixation electrophoresis (IFE). Direct bilirubin interference disap- peared after removal of the paraprotein by polyethylene glycol (PEG) precipitation. Laboratory specialist should know paraprotein interference and be able to manage it. Keywords: Monoclonal Gammopathy, paraprotein inter- ference, direct bilirubin Özet: Bu çalışmamızda laboratuar sonuçlarında parapro- teinemiye bağlı interferans saptanan bir hasta tanımlandı. Total protein konsantrasyonu 10.8 g/dL olan hastada totalden daha yüksek direkt bilirubin sonucu saptandı. Hastanın total kan sayımı parametrelerinde de uyum- suzluk vardı. Bu hastada ileri incelemeler yapıldı. Önce- likli olarak soğuk aglütinin ve kriyoglobulin test edilerek dışlandı. 2-mercaptoethanol (2-ME) ile muamele sonrası yapılan immünfiksasyon elektroforezinde (IFE) hasta Ig-M Kappa monoklonal gammapatisi olarak tanımlandı. Polyethylene glycol (PEG) presipitasyonu ile paraprote- inlerin ayrılması sonrası direkt bilirubin interferansı kay- boldu. Laboratuar uzmanları paraprotein interferansları konusunda bilgi sahibi olup bu konuyu yönetebilmelidir. Anahtar Kelimeler: Monoklonal gammapati, paraprotein interferansı, direkt bilirubin Introduction Monoclonal gammopathy is characterized by the presence of a monoclonal immunoglobulin or paraprotein in the serum or urine and occurs in clinical situations as multi- ple myeloma, Waldenstrom’s macroglobulinemia (WM), plasmacytoma, amyloidosis and monoclonal gammopathy of undetermined significance. Monoclonal gammopathies may or may not be together with cryoglobulins. In cryo- globulinemias, there is mono, oligo- or polyclonal immuno- globulins (cryoglobulins) precipitating at low temperatures and re-solubilize with warming. Type 1 cryoglobulinemia is associated with IgM gammopathy of Waldenstrom’s disease [1]. The cold agglutination disease is another situation in *Corresponding author: Özlem Çakır Madenci: Dr. Lütfi Kırdar Kartal Training and Research Hospital, Clinical Biochemistry Laboratory, İstanbul, Turkey, e-mail: ocmadenci@hotmail.com Nihal Yücel: Dr. Lütfi Kırdar Kartal Training and Research Hospital, Clinical Biochemistry Laboratory, İstanbul, Turkey, e-mail: yucel.nihal@yahoo.com Lale Köroğlu Dağdelen: Dr. Lütfi Kırdar Kartal Training and Research Hospital, Clinical Biochemistry Laboratory, İstanbul, Turkey, e-mail: laledagdelen@gmail.com Yusuf Temel: Dr. Lütfi Kırdar Kartal Training and Research Hospital, Clinical Biochemistry Laboratory, İstanbul, Turkey, e-mail: yusuftemel@hotmail.com.tr Aycan Bölük: Dr. Lütfi Kırdar Kartal Training and Research Hospital, Clinical Biochemistry Laboratory, İstanbul, Turkey, e-mail: aycanboluk@hotmail.com Asuman Orçun Kaptanağası: Dr. Lütfi Kırdar Kartal Training and Research Hospital, Clinical Biochemistry Laboratory, İstanbul, Turkey, e-mail: asumanorcun@yahoo.com