Protein Electrophoresis, Serum Free Light Chain Assay and Other Biomarkers in Diagnosis and Monitoring of Monoclonal Protein Associated Disease

Author(s):  
Stanley S. Levinson
Blood ◽  
2004 ◽  
Vol 104 (11) ◽  
pp. 4856-4856
Author(s):  
Arthur R. Bradwell ◽  
Jean Garbincius ◽  
Earle W. Holmes

Abstract Serum free light chain measurements have been shown to be useful in the diagnosis and monitoring of patients with monoclonal gammopathies. The present study was undertaken to evaluate the effect of adding the measurement of serum free light chain kappa to lambda ratios to the serum protein electrophoresis evaluation that we typically use as an initial screen for the detection of monoclonal proteins. We retrospectively tested 347 consecutive samples from individuals who had no previous history of plasma cell dyscrasia and had not previously had a serum or urine electrophoresis or immunofixation electrophoresis test at our institution. The quantitative serum protein electrophoresis test that was ordered was performed using Hydragel Beta 1- Beta 2 gels and Hydrasis instrument (Sebia, Inc., Norcross, GA). The protein content of the electrophoresis zones were quantitated by scanning densitometry and the electrophoresis pattern of each sample was qualitatively examined for abnormal bands and suspicious findings by a single, experienced observer. Serum free light chain concentrations and the serum free light chain kappa to lambda ratios were determined using the Freelite Human Kappa and Lambda Kits (The Binding Site Ltd, Birmingham, UK) and the Immage analyzer (Beckman Coulter Inc., Brea, CA). The serum free light chain kappa to lambda ratios were outside the reference interval (0.25 to1.65) in 23 of the samples. Ten abnormal ratios were observed among a group of 57 samples that had either positive or suspicious qualitative evaluations for the presence of a restriction or that demonstrated hypo-gammaglobulinemia. Both abnormalities led to recommendations for follow-up testing, which confirmed the presence of a monoclonal protein in 21 of the samples. Six abnormal ratios were observed among a group of 159 specimens that had quantitative abnormalities in albumin or one or more of globulin fractions (hypo-gammaglobulinemia excepted) and normal qualitative evaluations. Seven abnormal ratios were observed among a group of 131 samples that had normal quantitative results and normal qualitative evaluations. Follow-up testing is not usually recommended for serum protein electrophoresis results like those in the latter two groups. We found that the addition of the serum free light chain kappa to lambda ratio to the serum protein electrophoresis test increased the number of abnormal screens that would have required further clinical and/or laboratory evaluation by 23%(i.e. from 57 to 70). Given the high specificity of the serum free light chain kappa to lambda ratio for monoclonal light chains, the additional 13 abnormal samples identified by this test are expected to have a high likelihood of harboring a monoclonal protein that would have otherwise eluded detection. Pending a definitive prospective study, we estimate that the addition of a serum free light chain kappa to lambda ratio to the serum protein electrophoresis screen would increase the rate of detection of serum monoclonal proteins by as much as 1.6-fold.


2018 ◽  
Vol 93 (10) ◽  
pp. 1207-1210 ◽  
Author(s):  
Marcella Tschautscher ◽  
Vincent Rajkumar ◽  
Angela Dispenzieri ◽  
Martha Lacy ◽  
Morie Gertz ◽  
...  

Blood ◽  
2006 ◽  
Vol 108 (11) ◽  
pp. 5011-5011
Author(s):  
Jerry A. Katzmann ◽  
Angela Dispenzieri ◽  
Robert Kyle ◽  
Melissa R. Snyder ◽  
Mathew F. Plevak ◽  
...  

Abstract Due to the diagnostic sensitivity of serum free light chain quantitation for monoclonal light chain diseases, it has been suggested that urine assays no longer need be performed as part of the diagnostic algorithm for monoclonal proteins. We reviewed our experience to determine the relative diagnostic contribution of urine assays. Methods: Patients with a monoclonal gammopathy and monoclonal urinary protein at initial diagnosis who also had a serum immunofixation and serum free light chain quantitation within 30 days of diagnosis were identified (n = 428). The laboratory results for serum protein electrophoresis, serum immunofixation, serum free light chain, urine protein electrophoresis, and urine immunofixation were reviewed. Results: The patients in this cohort had diagnoses of multiple myeloma, primary amyloid, monoclonal gammopathy of undetermined significance, smoldering multiple myeloma, solitary plasmacytomas, and other less frequently detected monoclonal gammopathies. By definition of the cohort, all 428 had a monoclonal urine protein. 86% had an abnormal serum free light chain K/L ratio, 81% had an abnormal serum protein electrophoresis, and 94% had an abnormal serum immunofixation. In only 2 patients, however, were all 3 serum assays normal. Both of these were patients with monoclonal gammopathy of undetermined significance (idiopathic Bence Jones proteinuria). Conclusion: Discontinuation of urine studies and reliance on a diagnostic algorithm using solely serum studies (protein electrophoresis, immunofixation, and free light chain quantitation), missed 2 of the 428 monoclonal gammopathies (0.5 %) with urinary monoclonal proteins, and these 2 cases required no medical intervention.


Blood ◽  
2006 ◽  
Vol 108 (11) ◽  
pp. 5048-5048
Author(s):  
Jayesh Mehta ◽  
Regina Stein ◽  
Eric Vickrey ◽  
William Resseguie ◽  
Seema Singhal

Abstract The serum free light chain (SFLC) assay is useful in detecting monoclonal protein when there no detectable M protein on immunofixation electrophoresis (IFE). There are limited data on its value when IFE is positive. In a small series of 5 patients achieving CR, normalization of SFKLR was found to precede IFE negativity by a few weeks (Moesbauer et al. ASH 2005). Results on 231 serum samples from myeloma patients (most on therapy) where serum IFE showed IgA κ (n=33), IgA λ (n=13), IgG κ (n=153), or IgG λ (n=32), and where simultaneous SFLC and immunoglobulin (Ig) estimation had been performed were analyzed. Samples with >1 monoclonal band or multiple oligoclonal bands were excluded. The serum free κ:λ ratio (SFKLR; normal 0.26–1.65) was abnormal in 113 (49%) and normal in 118 (51%). IgG and IgA levels were compared in the context of normal versus abnormal SFKLR within each of the 4 isotypes (IgA κ, IgAλ, IgG κ, IgG λ). The table below shows that involved Ig levels were higher with abnormal than with normal SFKLR. However, uninvolved Ig levels were higher with normal than with abnormal SFKLR suggesting that normalization of SFKLR may mark a response to therapy - improved uninvolved Ig levels being evidence of response. Monoclonal protein Immunoglobulin Abnormal SFKLR Normal SFKLR P IgA kappa IgA 1640 (190–4000) 515 (102–2230) 0.048 IgA kappa IgG 419 (118–1120) 404 (197–1740) 0.39 IgA lambda IgA 408 (159–696) 704 (180–779) 0.17 IgA lambda IgG 619 (495–1510) 1530 (533–1700) 0.025 IgG kappa IgA 42 (7–225) 94 (7–642) 0.0009 IgG kappa IgG 1490 (585–5560) 1260 (327–2690) 0.004 IgG lambda IgA 32 (7–121) 96 (19–562) 0.047 IgG lambda IgG 2060 (555–12300) 1050 (432–2830) 0.018 However, does normalization of SFKLR universally herald IFE negativity? This is an important unanswered question because SFKLR is normal in a high proportion of samples which still show monoclonal protein on IFE. The figures below show scatter plots of IgG and IgA for each of the 4 isotypes for normal vs abnormal SFKLR. Within each plot, there is no obvious pattern distinguishing normal (x) from abnormal (o) SFKLR. However, there are a number of normal SFKLR points with high involved and low uninvolved Ig levels where a normal SFKLR is difficult to explain. Figure Figure Figure Figure We conclude that the SFLC assay often reveals normal SFKLR even when there is a detectable monoclonal protein in the serum. Whether this always predicts eventual paraprotein clearance and achievement of IFE negativity in patients on therapy is unknown, and needs to be studied prospectively.


2011 ◽  
Vol 57 (12) ◽  
pp. 1687-1692 ◽  
Author(s):  
Jerry A Katzmann ◽  
Melissa R Snyder ◽  
S Vincent Rajkumar ◽  
Robert A Kyle ◽  
Terry M Therneau ◽  
...  

BACKGROUND We analyzed serial data in patients with clinically stable monoclonal gammopathy to determine the total variation of serum M-spikes [measured with serum protein electrophoresis (SPEP)], urine M-spikes [measured with urine protein electrophoresis (UPEP)], and monoclonal serum free light chain (FLC) concentrations measured with immunoassay. METHODS Patients to be studied were identified by (a) no treatment during the study interval, (b) no change in diagnosis and <5 g/L change in serum M-spike over the course of observation; (c) performance of all 3 tests (SPEP, UPEP, FLC immunoassay) in at least 3 serial samples that were obtained 9 months to 5 years apart; (d) serum M-spike ≥10 g/L, urine M-spike ≥200 mg/24 h, or clonal FLC ≥100 mg/L. The total CV was calculated for each method. RESULTS Among the cohort of 158 patients, 90 had measurable serum M-spikes, 25 had urine M-spikes, and 52 had measurable serum FLC abnormalities. The CVs were calculated for serial SPEP M-spikes (8.1%), UPEP M-spikes (35.8%), and serum FLC concentrations (28.4%). Combining these CVs and the interassay analytical CVs, we calculated the biological CV for the serum M-spike (7.8%), urine M-spike (35.5%), and serum FLC concentration (27.8%). CONCLUSIONS The variations in urine M-spike and serum FLC measurements during patient monitoring are similar and are larger than those for serum M-spikes. In addition, in this group of stable patients, a measurable serum FLC concentration was available twice as often as a measurable urine M-spike.


Author(s):  
Richard B Fulton ◽  
Suran L Fernando

Background The potential for serum free light chain (sFLC) assay measurements to replace urine electrophoresis (uEPG) and to also diminish the need for serum immunofixation (sIFE) in the screening for monoclonal gammopathy was assessed. A testing algorithm for monoclonal protein was developed based on our data and cost analysis. Methods Data from 890 consecutive sFLC requests were retrospectively analysed. These included 549 samples for serum electrophoresis (sEPG), 447 for sIFE, and 318 for uEPG and urine immunofixation (uIFE). A total of 219 samples had sFLC, sEPG, sIFE and uEPG + uIFE performed. The ability of different test combinations to detect the presence of monoclonal proteins was compared. Results The sFLC κ/ λ ratio (FLC ratio) indicated monoclonal light chains in 12% more samples than uEPG + uIFE. The combination of sEPG and FLC ratio detected monoclonal proteins in 49% more samples than the combination of sEPG and sIFE. Furthermore, the sEPG + FLC ratio combination detected monoclonal protein in 6% more samples than were detected by the combined performance of sEPG, sIFE, uEPG and uIFE. However, non-linearity of the assay, the expense of repeat determinations due to the narrow measuring ranges, and frequent antigen excess checks were found to be limitations of the sFLC assay in this study. Conclusion The FLC ratio is a more sensitive method than uIFE in the detection of monoclonal light chains and may substantially reduce the need for onerous 24 h urine collections. Our proposed algorithm for the evaluation of monoclonal gammopathy incorporates the sFLC assay, resulting in a reduction in the performance of labour intensive sIFE and uEPG + uIFE while still increasing the detection of monoclonal proteins.


2020 ◽  
Vol 5 (6) ◽  
pp. 1358-1371
Author(s):  
Gurmukh Singh

Abstract Background Laboratory methods for diagnosis and monitoring of monoclonal gammopathies have evolved to include serum and urine protein electrophoresis, immunofixation electrophoresis, capillary zone electrophoresis, and immunosubtraction, serum-free light chain assay, mass spectrometry, and newly described QUIET. Content This review presents a critical appraisal of the test methods and reporting practices for the findings generated by the tests for monoclonal gammopathies. Recommendations for desirable practices to optimize test selection and provide value-added reports are presented. The shortcomings of the serum-free light chain assay are highlighted, and new assays for measuring monoclonal serum free light chains are addressed. Summary The various assays for screening, diagnosis, and monitoring of monoclonal gammopathies should be used in an algorithmic approach to avoid unnecessary testing. Reporting of the test results should be tailored to the clinical context of each individual patient to add value. Caution is urged in the interpretation of results of serum-free light chain assay, kappa/lambda ratio, and myeloma defining conditions. The distortions in serum-free light chain assay and development of oligoclonal bands in patients‘ status post hematopoietic stem cell transplants is emphasized and the need to note the location of original monoclonal Ig is stressed. The need for developing criteria that consider the differences in the biology of kappa and lambda light chain associated lesions is stressed. A new method of measuring monoclonal serum-free light chains is introduced. Reference is also made to a newly defined entity of light chain predominant intact immunoglobulin monoclonal gammopathy. The utility of urine testing in the diagnosis and monitoring of light chain only lesions is emphasized.


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