<prompt> Diagnostic investigation of Multiple myeloma:Lytic bone lesionsBence jones proteinsAlkaline PhosphataseSerum electrophoresis  <response>: Ans: d S. electrophoresis Ref: Harrison, 16th p. Davidson, 20th ed, p. 1052Confused? Option D is definitely better than option A. Eventhough both lytic bone lesions and S. electrophoresis are included in the diagnostic criteria, according to the diagnostic criteria defined by Salmon Durie, only monoclonal globulin spikes on S. electrophoresis is taken as major criteria. Lytic bone lesion is taken as a minor criteria only.Diagnosis of multiple myeloma The durie and salmon myeloma diagnostic criteria.The diagnosis of multiple myeloma requires a minimum of one major and one minor criteria or three minor criteria as defined in the Table below.Major criteria1 Plasmacytoma on tissue biopsy2 Bone marrow palsmacytosis with 30 plasma cells3 Monoclonal globulin spike M protein on SPEP: IgG3.5gdl, IgA 2.0gdl. light chain excretion in UPEP 1 g per 24 hr in the absence of amylodosis.Minor criteria1 Bone marrow plasmacytosis with 10-30 plasma cells2 Monclonal globulin spike present, but lower levels than defined in major criteria3 Lytic bone lesions4 Normal IgM 50 mgdl. IgA 100 mgdl, or IgG 600 mgdlThe diagnosis of myeloma requires a minimum of one major criteria and one minor criteria although 1 a is not sufficient or three minor criteria that must include ab.SPEP-serum protein electrophoresis. UPEP--urine protein electrophoresis 