The Czech National External Quality Assessment of monoclonal immunoglobulin in the period of 1996 - 2005.

The aim of the presented study was to evaluate the results of SEKK "Gammopathy" (GP) control cycle (Czech National External Quality Assessment) that assessed the success rate of monoclonal immunoglobulin determination by clinical laboratories for the 1996 - 2005 period. The study summarizes the results of 20 "Gammopathy" control cycles during the ten-year period. Control cycles were repeated every 6 months. Patients who provided samples for individual SEKK "Gammopathy" control cycles were selected during routine diagnostic process in the University Hospital Hradec Kralove. Correct paraprotein typing in both A and B control samples (plasma, serum or urine) is required prior to certification. Assessment of paraprotein concentration is optional. The number of participating laboratories was gradually increasing from 26 in 1996 to 79 in 2005 (including 6 Slovak laboratories). The majority of laboratories used immunofixation electrophoresis as the method of paraprotein typing. In 2005, only one laboratory was still using immunoelectrophoresis. Typing was successful in approximately 70% of cases during the first 3 cycles and the success rate gradually increased to almost 96% by 2005. The only exception was GP 1/02 cycle with a sample of relatively rare IgD-lambda paraprotein and the success rate of 38% only. A sample of plasma without paraprotein was distributed 4 times. Several laboratories falsely identified fibrinogen as paraprotein each time. Results of "Gammopathy" control cycle for the past 10 years confirmed the value and legitimacy of this control cycle in the system of external quality control of SEKK laboratories.