Background: The diagnosis of AL amyloidosis is based on histologic finding as well as on some laboratory tests. According to the most recent guidelines serum and urine immunofixation, and serum free light chain measure are of paramount importance. Objectives: With the present work we evaluated the performance of the above mentioned tests in 9 laboratories belonging to the Piedmont and Aosta Valley consortium for systemic amyloidosis through an External Quality Assurance (EQA). Methods: In 2010 all laboratories of Piedmont and Valle d'Aosta were invited to participate to an EQA in order to evaluate their performance in the identification of monoclonal components and the measure of free light chains in frozen serum samples. Nine laboratories joined the evaluation. Protein electrophoresis and immunofixation were performed in 3 laboratories by using capillary electrophoresis and in the remaining 6 by an automated gel electrophoresis. Sebia reagents (Evry, France) were used. Measure of free light chains was performed in 5 laboratories: 4 with the Binding Site Freelite method (Birmingham, UK) and 1 with New Scientific Company method (Fonegrò, Italy). Results: The assessment of monoclonal component by serum proteins electrophoresis and immunofixation showed an overall sensitivity of 100% and an overall specificity of 61%. The quantification of the monoclonal component showed a good agreement in the results even though a laboratory did not performed quantification and 3 more laboratories showed only a percentage and not quantification in g/l. Assessment of free light chains showed variations coefficient greater than 40% between laboratories. Discussion: While improved as compared to a previous EQA performed in 2009, the present EQA emphasized critical issues, especially in the determination of free light chains. Conclusion: The adoption of the same analytical method by all laboratories is probably needed in order to compare data from different laboratories and improve diagnostic sensitivity. The abstract has been written on behalf of all participants in the consortium.
External Quality Assurance (EQA) of Immunofixation and serum free light chain measure in 9 laboratories participating in the Piedmont and Aosta Valley consortium for systemic amyloidosis
BALDOVINO, Simone;SCIASCIA, Savino;ROCCATELLO, Dario
2012-01-01
Abstract
Background: The diagnosis of AL amyloidosis is based on histologic finding as well as on some laboratory tests. According to the most recent guidelines serum and urine immunofixation, and serum free light chain measure are of paramount importance. Objectives: With the present work we evaluated the performance of the above mentioned tests in 9 laboratories belonging to the Piedmont and Aosta Valley consortium for systemic amyloidosis through an External Quality Assurance (EQA). Methods: In 2010 all laboratories of Piedmont and Valle d'Aosta were invited to participate to an EQA in order to evaluate their performance in the identification of monoclonal components and the measure of free light chains in frozen serum samples. Nine laboratories joined the evaluation. Protein electrophoresis and immunofixation were performed in 3 laboratories by using capillary electrophoresis and in the remaining 6 by an automated gel electrophoresis. Sebia reagents (Evry, France) were used. Measure of free light chains was performed in 5 laboratories: 4 with the Binding Site Freelite method (Birmingham, UK) and 1 with New Scientific Company method (Fonegrò, Italy). Results: The assessment of monoclonal component by serum proteins electrophoresis and immunofixation showed an overall sensitivity of 100% and an overall specificity of 61%. The quantification of the monoclonal component showed a good agreement in the results even though a laboratory did not performed quantification and 3 more laboratories showed only a percentage and not quantification in g/l. Assessment of free light chains showed variations coefficient greater than 40% between laboratories. Discussion: While improved as compared to a previous EQA performed in 2009, the present EQA emphasized critical issues, especially in the determination of free light chains. Conclusion: The adoption of the same analytical method by all laboratories is probably needed in order to compare data from different laboratories and improve diagnostic sensitivity. The abstract has been written on behalf of all participants in the consortium.
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