Comparison of Freelite and N-Latex serum free light chain assays: a critical review

IntroductionThe measurement of serum free light chain (FLC) represents a fundamental aspect on the assessment of patients with monoclonal gammopathies (MG). Different analytical methods for FLC have become available with the possibility to obtain different value with a substantial impact on the assessment of patients with MG. This study aimed to evaluate FLC results obtained with two different assays and how the difference value obtained can impact in the patient’s assessment.Materials and methodsNinety-three patient serum samples that underwent analysis for FLC with two different methods, Serum Freelite (The Binding Site, Birmingham, UK) and N-Latex FLC (Siemens, Marburg, Germany), were included in this retrospective study. Statistical analysis was performed to evaluate correlation, difference, and the grade of concordance between the results obtained with the two methods.ResultsSignificant statistical differences between the results obtained from the two methods were found (P < 0.05). A good correlation was found (0.99 for κ FLC, 0.95 for λ FLC, and 0.94 for the κ/λ ratio, respectively). We found a weighted kappa value of 0.65 for κ/λ ratio, 0.65 for λ FLC and 0.90 for κ FLC. A positive bias found with the Bland-Altman plot mirrors overestimation of κ FLC and κ/λ ratio with Freelite compared to N-Latex, whilst a negative bias underscores underestimation of λ FLC by Freelite compared to N-Latex.ConclusionAlthough in general the concordance between Freelite and N-Latex appears satisfactory, several discrepancies could be evidenced and consequently the two assays are not interchangeable.     

Explorations of a Paradox in Curriculum Control: Resistance to Open-ended Science Inquiry in a School for Self-directed Learning

Despite official government srt (in various jurisdictions around the world) for providing students with opportunities to construct their own knowledge within the context of formal schooling, school science systems continue to place greatest priority on teaching and learning of products of science (e.g., laws and theories), while compromising students’ opportunities to develop realistic conceptions about science and expertise for doing science. Based on qualitative data analyzed using constant comparative methods (based on constructivist grounded theory), we found this also to be the case – paradoxically – in a school belonging to the Canadian Coalition for Self-directed Learning (CCSDL). Schools in this coalition espouse, among various goals, enabling students to construct their own knowledge, in ways and directions suiting their individual needs, interests, perspectives, and abilities, in addition to gaining access to knowledge developed by society. The science department within the coalition school in this study experienced considerable difficulty realizing this goal, despite school-level administrative support for a concerted effort to reinvent itself along these lines. Factors that appeared to influence the science department’s efforts included those in each of Schwab’s (1969) educational "commonplaces;” that is, the curriculum, teachers, students, and the milieu surrounding teaching and learning. Further analysis suggests that results can be explained through reference to a Kuhnian (1962/1996) paradigm conflict – in which the school’s administrative and curricular committee and other members of the CCSDL were unsuccessful in convincing members of the science department (who, in turn, appeared to be supported by the provincial government, parents, and students) to make provisions for more student-directed, openended science inquiry. Assuming that student-led scientific inquiry continues to be an important curricular goal, efforts must continue to be made, therefore, to convince members of the mainstream paradigm that it is a worthy goal.