Naslov
Interference of M-protein on prothrombin time : case report

Autori
Margetić, Sandra ; Ćelap, Ivana ; Dukić, Lora ; Vukasović, Ines ; Virović-Jukić, Lucija

Izvornik
Biochemia medica (1330-0962) 26 (2016), 2; 248-254

Vrsta, podvrsta i kategorija rada
Radovi u časopisima, pregledni rad, znanstveni

Ključne riječi
prothrombin time ; interference ; M-protein ; monoclonal gammopathy ; thrombin time

Sažetak
The aim of this report wasto present a case of interference on prothrombin time (PT) test that directed further laboratory diagnostics and resulted with final detection of monoclonal gammopathy in an 88-year old man. Routine coagulation testing during medical examination at Emergency Department revealed unmeasurable PT (<7% activity) and activated partial thromboplastin time (aPTT) within reference range. After repeated sampling for coagulation testing, PT was unmeasurable again, as well as fibrinogen level (<0.8 g/L), thrombin time (TT) was significantly prolonged (107 seconds) and aPTT was within reference range. In both plasma samples refrigerated at 4˚C overnight, white gelatinous precipitate was visible between the cell and plasma layers and the presence of monoclonal protein (M-protein) was suggested in our patient. Further laboratory diagnostics revealed total serum proteins at concentration of 123 g/L and the presence of M-protein IgG lambda (λ) at concentration of 47.1 g/L. These results suggested monoclonal gammopathy as an underlying pathophysiological condition in our patient. Activities of coagulation factors II, V, VII and X were within reference ranges or increased in both, native plasma sample with unmeasurable PT result as well as in plasma sample after separating precipitate. These results and correction of unmeasurable PT result to 67% in mixing test with commercial normal plasma suggest in vitro rather than in vivo interference of M-protein on PT result. In contrast, significantly prolonged TT results in all analysed samples suggest in vivo interference of M-protein on this global coagulation test with possible effect on fibrin polymerization.

Izvorni jezik
Engleski

Znanstvena područja
Kliničke medicinske znanosti

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