title: An IgE multiple myeloma: contradictory findings in clinical laboratory testing.
abstract: BACKGROUND
  IgE multiple myeloma is a rare kind of plasma cell disorder, characterized by an aggressive clinical course, where laboratory testing plays a fundamental role for the correct diagnosis in order to start a targeted therapy. In the present paper it is described a case of IgE myeloma where contradictory findings between immunometric and separative techniques were found.
  
  
  METHODS
  Serum and 24h urine samples were tested using electrophoresis and immunofixation electrophoresis employing IgE antiserum and IgE were quantified using an immunometric method.
  
  
  RESULTS
  Serum immunofixation evidenced a monoclonal band ascribable to IgE lambda and IgE serum concentration was 1,364,00 kU/L. Urine electrophoresis evidenced a band compatible with IgE, and urine concentration was 2715 kU/L. On the contrary in the immunofixation of the urine sample no band reacting with IgE antiserum was found.
  
  
  CONCLUSIONS
  Considering that the immunometric method measured IgE in urine sample and the electrophoresis of urine sample evidenced a band compatible with IgE, the explanation could be that during renal filtration or because of some characteristics related to urine matrix, the immunoglobulin IgE could had been modified in the site recognized by the antiserum used in immunofixation, and not in the one used in the immunometric method.
authors.affiliation: Department of Laboratory Medicine, University-Hospital of Padova, Italy. Electronic address: sara.altinier@sanita.padova.it.
authors.forename: Sara
authors.initials: S
authors.lastname: Altinier
authors.forename: Giuseppina
authors.initials: G
authors.lastname: Barberio
authors.forename: Mariacristina
authors.initials: M
authors.lastname: Varagnolo
authors.forename: Martina
authors.initials: M
authors.lastname: Zaninotto
authors.forename: Anna
authors.initials: A
authors.lastname: Furlan
authors.forename: Livio
authors.initials: L
authors.lastname: Caberlotto
authors.forename: Mario
authors.initials: M
authors.lastname: Plebani
mesh_terms: D015982:Bias; D003955:Diagnostic Tests, Routine / Q000592:standards*; D019075:Electrophoresis, Capillary; D006801:Humans; D007106:Immune Sera / Q000737:chemistry; D007118:Immunoassay / Q000592:standards*; D007073:Immunoglobulin E / Q000097:blood / Q000652:urine; D008297:Male; D008875:Middle Aged; D009101:Multiple Myeloma / Q000097:blood / Q000175:diagnosis* / Q000652:urine
chemical_list: D007106:Immune Sera; D007073:Immunoglobulin E
keywords: Capillary electrophoresis; IgE multiple myeloma; Immunofixation; Urinary electrophoresis