Objective: To analyse the results of the „Gammopathies“ control system which evaluate a successfulness of clinical laboratories in determination of a type of monoclonal immunoglobulins during the period of 1996–2005. Design: The study gives a survey of the results of twenty „Gammopathies“ control cycles during the period of ten years. The control cycles are organized twice a year. Material and Methods: Patients for blood taking samples in the control cycles are selected in the course of a routine diagnostics in the University Hospital, Hradec Králové. After centrifugation, the plasma is storaged at -30 oC. A correct typing of paraprotein in both control samples A and B (plasma,serum or urine) is required for conformation of a certificate. The determination of paraprotein concentration is an optional step. Results: The number of participated laboratories gradually increased from 26 in the year 1996 to 79 in the year 2005 (6 from Slovakia). For typing of paraproteins, immunofixation electrophoresis is applied in most laboratories. Only one laboratory in the Czech Republic used immunoelectrophoresis in the year 2005.A success of typing in the first 3 cycles was around 70% and in the year 2005 reached 96%. The exception was the cycle GP1/02 with relatively rare paraprotein IgD-lambda sample when laboratories succeeded only in 38%.The samples of plasma without paraprotein were sent four times and several laboratories always made a wrong identification of fibrinogen like paraprotein. In the cycle GP1/03, the samples with low concentrations of paraprotein in blood serum (1.46 g/l) and in urine (0.113 g/l) were used with very good results (89%). On the contrary, the samples with extreme concentrations of paraproteins (57.8 g/l for IgM-kappa and 42.2 g/l for IgG-lambda) were distributed in the cycle GP2/03 also with the efficiency of 89%. Determination of paraprotein concentrations has been also improving gradually.This determination is voluntary and on average 68% of laboratories take part in there. Conclusion: The results of „Gammopathies“ control system confirmed usefulness and validity of implementation of this cycle into the national external quality assessment system „SEKK“. The Czech national external quality assessment of monoclonal immunoglobulin markedly contributes to enhancing a quality of determination and partially to a quantification of monoclonal immunoglobulins as well.

        Key words: monoclonal immunoglobulin, paraprotein, monoclonal gammopathie, external quality assessment system.