Authors: K. Vilímová 1; P. Kušnierová 1,2 Authors‘ workplace: Ústav laboratorní medicíny, Oddělení klinické biochemie, Fakultní nemocnice Ostrava, Ostrava 1; Ústav laboratorní medicíny, Lékařská fakulta, Ostravská univerzita, Ostrava 2 Published in: Klin. Biochem. Metab., 32, 2024, No. 2, p. 43-48 doi: https://doi.org/10.61568/kbm.2024.008
Objective: The aim of the study was to assess the basic analytical characteristics of the isoelectric focusing followed by affinity immunoblotting (IEF/AIB) method for the detection of monoclonal free light chains (FLC), its comparison with routinely available methods and its use in distinguishing monoclonal or oligoclonal character of free light chains. Methods: A total of 94 serum and urine samples of patients from various specialist outpatient clinics in the Moravian-Silesian Region with suspected monoclonal gammopathy were included in the study. Serum protein electrophoresis, immunofixation electrophoresis and IEF/AIF were used to detect the monoclonal component. MS Excel and MedCalc software were used for statistical data processing. Results: The IEF/AIB is a highly sensitive method with a limit of quantification of around 0.025 mg/L for FLC kappa and 0.25 mg/L for FLC lambda, in contrast to serum protein electrophoresis and immunofixation electrophoresis. When assessing the methods on the basis of agreement of clinical interpretation, 100% agreement (κ = 1.0) was achieved between IMF and IEF/AIB methods for the detection of monoclonal free light chains in serum and 92.6% and 94.4% for the detection of monoclonal free light chains kappa and lambda in urine (κ = 0.844 respectively 0.886). Comparing the results of patients with a proven oligoclonal kappa and lambda free light chain profile by IMF with IEF/AIB, 75% respectively 68.8% agreement was obtained (κ = 0.215 respectively 0.076), indicating that the IEF/AIB method was able to detect monoclonal serum free light chains in 25 % respectively 30.2 % of samples, which were misinterpreted as oligoclonal profiles by the IMF method. Conclusion: The method of isoelectric focusing followed by affinity immunoblotting is a highly sensitive method that can detect the presence of monoclonal immunoglobulin when serum protein electrophoresis and immunofixation electrophoresis are negative or distinguish between monoclonal and oligoclonal immunoglobulin free light chain profiles.
monoclonal immunoglobulin – immunofixation electrophoresis – oligoclonal profile – serum protein electrophoresis – isoelectric focusing followed by affinity immunoblotting
Don‘t have an account? Create new account
Enter the email address that you registered with. We will send you instructions on how to set a new password.
