Artefactual decrease in total protein concentration in patients with monoclonal gammopathies: a method-dependent error.
We found total protein estimates in patients with monoclonal gammopathies to be erroneously low when using the Cobas-Bio centrifugal analyzer. This problem occurred only when a serum-water blank was used. This probably results from the precipitation of these proteins under conditions of low ionic strength resulting in high blank readings. The problem can be avoided if a serum-saline blank is used.
D001774:Blood Chemical Analysis / Q000295:instrumentation*; D001798:Blood Proteins / Q000032:analysis*; D005069:Evaluation Studies as Topic; D005188:False Negative Reactions; D006801:Humans; D008012:Lidocaine / Q000031:analogs & derivatives; D009101:Multiple Myeloma / Q000097:blood*; D009194:Myeloma Proteins / Q000097:blood*; D010266:Paraproteins / Q000097:blood*; D008258:Waldenstrom Macroglobulinemia / Q000097:blood*
D001798:Blood Proteins; D009194:Myeloma Proteins; D010266:Paraproteins; C042952:ethylmethylglycinexylidide; D008012:Lidocaine