title: Quantitation of serum free light chains in combination with protein electrophoresis and clinical information for diagnosing multiple myeloma in a general hospital population.
abstract: BACKGROUND
  Serum free light chain (SFLC) measurements have recently come into use as an aid for diagnosing monoclonal gammopathy. We evaluated SFLC measurements in combination with serum protein electrophoresis (SPE) and clinical information for diagnosing multiple myeloma (MM) in a hospital population.
  
  
  METHODS
  We measured SFLCs in 3818 sera received for SPE over a 1-year period when patient symptoms or biochemical findings suggested myeloma-related tissue damage (n = 1067). We reviewed SPE and SFLC results from 489 patients together with their final diagnoses obtained from the hospital information technology department.
  
  
  RESULTS
  SFLC measurement, combined with SPE and clinical information, allowed identification of 95% of patients (38 of 40) with previously undiagnosed MM, macroglobulinemia, or primary amyloidosis. Additionally, we identified 45 patients with monoclonal gammopathy of undetermined significance (MGUS) and 4 with plasmacytoma. Of patients followed at our hospital in whom SFLCs were not measured, only 1 patient was diagnosed with MM. This patient had anemia and was mistakenly not tested for SFLCs. An abnormal kappa/lambda ratio was found in 26 of 29 patients with MM but also in 36 of 203 patients with renal impairment, polyclonal immunoresponse, or other nonhematological diagnoses. None of the 203 patients with nonhematological disease had a kappa/lambda ratio <0.05 or >10.
  
  
  CONCLUSIONS
  The combined use of SPE, SFLC measurements, and clinical criteria allows MM to be efficiently diagnosed or excluded based on serum measurements only.
authors.affiliation: Department of Clinical Chemistry, Ulleval University Hospital, Oslo, Norway. armin.piehler@medisin.uio.no
authors.forename: Armin P
authors.initials: AP
authors.lastname: Piehler
authors.forename: Nina
authors.initials: N
authors.lastname: Gulbrandsen
authors.forename: Peter
authors.initials: P
authors.lastname: Kierulf
authors.forename: Petter
authors.initials: P
authors.lastname: Urdal
mesh_terms: D004586:Electrophoresis / Q000379:methods*; D006801:Humans; D007147:Immunoglobulin Light Chains / Q000097:blood* / Q000302:isolation & purification; D007297:Inpatients; D009101:Multiple Myeloma / Q000097:blood / Q000175:diagnosis*
chemical_list: D007147:Immunoglobulin Light Chains