RESUMO
Urinary protein electrophoresis analysis (UPE) is an essential investigation for the study of abnormal proteins in urines. The interpretation of this analysis must be comprehensive and relevant. Indeed, UPE is often requested by clinicians and may have an important impact in patient's management. This paper presents two cases with free light chains showing unexpected electrophoretic migration which can lead to the misinterpretation of results. This article helps biologists to keep in mind the interest of UPE among the several analyses useful in the laboratory.
Assuntos
Cadeias Leves de Imunoglobulina/urina , Cadeias kappa de Imunoglobulina/urina , Mieloma Múltiplo/urina , Proteinúria/diagnóstico , Urinálise/métodos , Idoso , Diagnóstico Diferencial , Erros de Diagnóstico , Eletroforese , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Gamopatia Monoclonal de Significância Indeterminada/diagnóstico , Gamopatia Monoclonal de Significância Indeterminada/urina , Mieloma Múltiplo/diagnóstico , Proteinúria/urinaRESUMO
BACKGROUND: The monitoring of phlebotomies in hemochromatosis patients depends on iron status measured by ferritin and transferrin saturation (TS). However, in the presence of inflammation or liver injury, soluble transferrin receptor (sTfR) determination was proposed to replace ferritin for diagnosing iron deficiency (ID). The present study evaluated performances of sTfR for the prediction of iron deficiency in a large number of hemochromatosis patients under phlebotomy therapy. METHODS: We studied 52 patients undergoing therapeutic phlebotomies and obtained 2 samples from 37 patients. Biological parameters were determined before each phlebotomy began. Performances of sTfR and TS in the diagnosis of iron deficiency were compared, according to ferritin levels under 12 microg/l. RESULTS: Ferritin and TS were correlated with removed iron (r=0.473, p<0.005 and r=0.345, p<0.05, respectively) and sTfR was correlated with the decrease in hemoglobin levels induced by phlebotomies (r=-0.678, p<0.0001). Areas under Receiver Operating Characteristics (ROC) curves for sTfR and TS were not statistically different for prediction of iron deficiency and sensitivity/specificity of sTfR at 1.64 mg/l were 67/86%. CONCLUSIONS: sTfR determination could be used to predict iron depletion induced by phlebotomies when ferritin is of limited interest, to avoid the appearance of anemia.