scholarly journals Serum free light chain assay reduces the need for serum and urine immunofixation electrophoresis in the evaluation of monoclonal gammopathy

2009 ◽  
Vol 46 (5) ◽  
pp. 407-412 ◽  
Author(s):  
Richard B Fulton ◽  
Suran L Fernando
Keyword(s):  
Light Chain ◽  
Monoclonal Gammopathy ◽  
Free Light Chain ◽  
Light Chains ◽  
Serum Free ◽  
Monoclonal Protein ◽  
Serum Free Light Chain ◽  
Immunofixation Electrophoresis ◽  
Monoclonal Proteins ◽  
Testing Algorithm

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.

Lambda monoclonal free light chain abnormalities detected by a serum immunofixation electrophoresis assay are underrepresented by quantitative serum free light chain results

2021 ◽  
Vol 156 (Supplement_1) ◽  
pp. S13-S14
Author(s):  
Rebecca Treger ◽  
Kathleen Hutchinson ◽  
Andrew Bryan ◽  
Chihiro Morishima
Keyword(s):  
Light Chain ◽  
Free Light Chain ◽  
Light Chains ◽  
Sample Population ◽  
Free Light Chains ◽  
Serum Free ◽  
Serum Free Light Chain ◽  
Immunofixation Electrophoresis ◽  
High Concordance ◽  
Polyclonal Antisera

Abstract Protein and immunofixation (IFIX) electrophoresis are used to diagnose and monitor monoclonal gammopathies. While IFIX detects clonal production of intact immunoglobulins and free light chains (FLC), the latter can also be quantified using a serum free light chain (SFLC) assay, in which polyclonal antisera detects epitopes specific for free kappa (KFLC) or lambda light chains (LFLC). An abnormal KFLC: LFLC ratio (KLR) serves as a surrogate for clonality. While the SFLC assay is highly sensitive, normal LFLC (<2.63mg/dL) and KLR results (>0.26 & <1.65) were found in samples with distinct lambda monoclonal free light chains visualized by IFIX (X-LMFLC). To investigate this discordance, contemporaneous SFLC or KLR values were evaluated for their ability to accurately classify monoclonal FLCs identified by IFIX. We performed a retrospective analysis of serum and urine IFIX (Sebia Hydrasys) and SFLC (Freelite®, Binding Site) results from our institution between July 2010 through December 2020, using R 4.0.2 and Tidyverse packages. From among 9,594 encounters in which a single monoclonal component was initially identified by IFIX, 157 X-LMFLC and 131 X-KMFLC samples were analyzed. Elevated LFLC with normal KFLC was identified in 105/157 X-LMFLC samples (67%), while both LFLC and KFLC were elevated in 42/157 samples (27%). Concordance between X-KMFLC and KFLC was markedly higher, where 122/131 samples (93%) displayed elevated kappa FLC (>1.94mg/dL) with normal LFLC, and only 7/131 X-KMFLC samples (5%) possessed both elevated KFLC and LFLC. The use of KLR to identify pathogenic monoclonal free light chains improved lambda concordance to 85%; however, 19/157 (12%) of X-LMFLC samples still exhibited normal KLR. High concordance of 98% was again observed for X-KMFLC with abnormal KLR. When samples were segregated according to normal or impaired renal function (eGFR > or ≤60mL/min/1.73m², respectively), this disparate identification of X-LMFLC and X-KMFLC by the SFLC assay persisted, suggesting that renal dysfunction (as measured by eGFR) does not underlie this phenomenon. Lastly, we corroborated the above findings in a larger sample population by examining patients with urine Bence Jones FLC identified by IFIX who had free or intact monoclonal components in serum (N=724), grouped by lambda or kappa light chain involvement. The cause(s) of the discrepant performance by the Freelite® SFLC assay, relative to the Sebia Hydrasys IFIX assay, for identifying lambda FLC components is currently unclear. Possible contributory factors include assay reference range cutoffs, other patient disease parameters, and differences in assay-specific polyclonal antisera. Future analyses of these factors will help to further characterize SFLC assay performance and elucidate how interpretation of composite serum FLC test results can be improved to better guide patient management.

Serum Free Kappa to Free Lambda Ratios as an Adjunct to Serum Protein Electrophoresis for the Detection of Monoclonal Proteins in the Serum.

Blood ◽  
2004 ◽  
Vol 104 (11) ◽  
pp. 4856-4856
Author(s):  
Arthur R. Bradwell ◽  
Jean Garbincius ◽  
Earle W. Holmes
Keyword(s):  
Serum Protein ◽  
Light Chain ◽  
Protein Electrophoresis ◽  
Free Light Chain ◽  
Serum Protein Electrophoresis ◽  
Serum Free ◽  
Monoclonal Protein ◽  
Serum Free Light Chain ◽  
Monoclonal Proteins

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.

Elimination of the Need for Urine Studies during Diagnostic Studies of Monoclonal Gammopathies by the Combined Use of Serum Immunofixation and Serum Free Light Chain Assays.

Blood ◽  
2006 ◽  
Vol 108 (11) ◽  
pp. 5011-5011
Author(s):  
Jerry A. Katzmann ◽  
Angela Dispenzieri ◽  
Robert Kyle ◽  
Melissa R. Snyder ◽  
Mathew F. Plevak ◽  
...  
Keyword(s):  
Light Chain ◽  
Monoclonal Gammopathy ◽  
Diagnostic Algorithm ◽  
Protein Electrophoresis ◽  
Free Light Chain ◽  
Urine Protein ◽  
Serum Free ◽  
Monoclonal Gammopathies ◽  
Serum Free Light Chain ◽  
Monoclonal Proteins

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.

Significance of Serum Free Light Chain Estimation with Detectable Serum Monoclonal Protein on Immunofixation Electrophoresis.

Blood ◽  
2006 ◽  
Vol 108 (11) ◽  
pp. 5048-5048
Author(s):  
Jayesh Mehta ◽  
Regina Stein ◽  
Eric Vickrey ◽  
William Resseguie ◽  
Seema Singhal
Keyword(s):  
Light Chain ◽  
Free Light Chain ◽  
Response To Therapy ◽  
Oligoclonal Bands ◽  
Serum Samples ◽  
Serum Free ◽  
Monoclonal Protein ◽  
Serum Free Light Chain ◽  
Small Series ◽  
Immunofixation Electrophoresis

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.

The Relationship Between Serum Free Light Chain Levels and Urine Protein in Patients with IgG or IgA Myeloma.

Blood ◽  
2009 ◽  
Vol 114 (22) ◽  
pp. 1810-1810
Author(s):  
J. Mehta ◽  
E. Vickrey ◽  
D. Ramadurai ◽  
E. Voigt ◽  
C. Fitzpatrick ◽  
...  
Keyword(s):  
Light Chain ◽  
Gold Standard ◽  
Free Light Chain ◽  
Light Chains ◽  
Urine Collection ◽  
Urine Protein ◽  
Serum Free ◽  
Monoclonal Protein ◽  
Serum Free Light Chain ◽  
The Relationship

Abstract Abstract 1810 Poster Board I-836 The serum free light chain (SFLC) assay is often though to be a replacement for the cumbersome process of 24-hour urine collection for monoclonal protein estimation (http://www.freelite.co.uk/initialinvestigationpro-24.asp; accessed 16 July 2009) despite evidence suggesting that SFLC estimation cannot replace urine protein quantification (Singhal et al. Blood 2007; 109:3611-2). We studied results from patients with IgG or IgA myeloma if all the following criteria were satisfied: concomitant SFLC and 24-hour urine specimens analyzed, no oligoclonal proteins, no diminished free light chain levels (involved or uninvolved). The aim was to study the correlation between SFLC and 24-hour urine total protein (24UTP), 24-hour urine monoclonal protein (24UMP) and urine immunofixation electrophoresis (UIFE). Only concordant abnormal SFLC ratios were considered abnormal (Singhal et al. Blood 2009; 114:38-9). 558 samples in 114 patients were identified. SFLC ratio was abnormal in 242 and normal in 316 (including 2 discordant abnormal). UIFE (available in 540) was negative in 290. The proportion of samples with normal SFLC ratio decreased as 24UTP increased (P<0.001): ≤200 mg - 75% of 243, 200-500 mg 33% of 129, 501-1000 mg - 24% of 54, and >1000 mg - 6% of 32. Similarly, the proportion of samples with normal SFLC ratio declined as 24UMP increased (P=0.001): ≤200 mg (including negative) - 41% of 145, 200-500 mg 4% of 28, 501-1000 mg - 0% of 14, and >1000 mg - 0% of 15. SFLC ratio was normal in 84% of samples with negative UIFE and in 26% of samples with positive UIFE (P<0.0001). Among the 47 samples with abnormal SFLC ratio and negative UIFE, the 24UTP was 47-288 mg (median 112). 24UMP was 35 mg in 1, “faint” in 1, and no restricted bands were seen in ther remaining 45. The table shows the relationship between UPEP, UIFE and SFLC amongst the 540 samples where all 3 tests were available. The presence of any restricted band on UPEP, even if too small to quantify, was considered positive. n=540 Positive UPEP Negative UPEP Positive UIFE Negative UIFE Positive UIFE 222 28 Negative UIFE 17 273 Abnormal SFLC ratio 172 59 184 47 Normal SFLC ratio 67 242 66 243 If a positive UPEP is considered the “gold standard” evidence of the presence monoclonal light chains in the urine, the sensitivity of UIFE in detecting urine monoclonal protein is 93% and that of an abnormal SFLC ratio is 72%. On the other hand, if a positive UIFE is considered the “gold standard” evidence of monoclonal light chains in the urine, the sensitivity of an abnormal SFLC ratio in detecting urine monoclonal protein is 74%. These data, obtained from a much large number of homogeneous clinical samples, confirm our previous observations (Singhal et al. Blood 2007; 109:3611-2) that an abnormal SFLC ratio cannot consistently predict the presence of either non-specific or monoclonal proteinuria. Fortunately, the proportion of urine samples with large aounts of non-specific or monoclonal proteinuria that is associated with normal SFLC ratios is small. The sensitivity of the SFLC ratio in detecting urine monoclonal protein is less than that of UIFE. The SFLC assay cannot replace 24-hour urine collection in clinical practice without compromising patient care. Whether a less cumbersome technique such as a spot (random) urine protein-creatinine ratio - used in conjunction with the SFLC assay - can avert the need for 24-hour urine collections in myeloma patients remains to be investigated. Disclosures No relevant conflicts of interest to declare.

scholarly journals Serum free light chain measurements to reduce 24-h urine monitoring in patients with multiple myeloma with measurable urine monoclonal protein

2018 ◽  
Vol 93 (10) ◽  
pp. 1207-1210 ◽  
Author(s):  
Marcella Tschautscher ◽  
Vincent Rajkumar ◽  
Angela Dispenzieri ◽  
Martha Lacy ◽  
Morie Gertz ◽  
...  
Keyword(s):  
Multiple Myeloma ◽  
Light Chain ◽  
Free Light Chain ◽  
Serum Free ◽  
Monoclonal Protein ◽  
Serum Free Light Chain

The relationship between the serum free light chain assay and serum immunofixation electrophoresis, and the definition of concordant and discordant free light chain ratios

Blood ◽  
2009 ◽  
Vol 114 (1) ◽  
pp. 38-39 ◽  
Author(s):  
Seema Singhal ◽  
Eric Vickrey ◽  
Jairam Krishnamurthy ◽  
Veerpal Singh ◽  
Sharon Allen ◽  
...  
Keyword(s):  
Light Chain ◽  
Normal Serum ◽  
Free Light Chain ◽  
Serum Free ◽  
Serum Free Light Chain ◽  
Immunofixation Electrophoresis ◽  
Serial Samples ◽  
Definition Of ◽  
The Relationship

Abstract“Stringent” complete remission in myeloma has been defined by a normal serum free light chain ratio (SFLCR) in addition to the standard criteria for CR. 2648 serial samples from 122 IgG or IgA myeloma patients were studied to explore the relationship between SFLCR and serum immunofixation electrophoresis (SIFE). SFLCR was normal in 34% of cases with positive SIFE and abnormal in 66%. SFLCR was normal in 69% of cases with negative SIFE and abnormal in 31%. When evaluated with SIFE as the benchmark, the sensitivity of SFLCR was 66% and specificity was 69%. These findings were unchanged when abnormal SFLCR values were classified as concordant (< 0.26 for λ disease and > 1.65 for κ) or discordant (< 0.26 for κ disease and > 1.65 for λ). Additional studies are required to determine the temporal relationship between SFLCR normalization and paraprotein clearance. Until then, the role of SFLCR in defining response remains controversial.

scholarly journals In-house age-specific reference ranges for free light chains measured on the SPAPlus® analyser

2020 ◽  
Vol 57 (2) ◽  
pp. 138-143
Author(s):  
Lauren Campbell ◽  
Dawn Simpson ◽  
Adrian Shields ◽  
Berne Ferry ◽  
Karthik Ramasamy ◽  
...  
Keyword(s):  
Glomerular Filtration Rate ◽  
Light Chain ◽  
Filtration Rate ◽  
Estimated Glomerular Filtration Rate ◽  
Free Light Chain ◽  
Light Chains ◽  
Reference Ranges ◽  
Free Light Chains ◽  
Serum Free ◽  
Serum Free Light Chain

Background The measurement of monoclonal free light chains is being increasingly utilized since the introduction of serum-based assays. It is important for laboratories to determine their own reference ranges in order to reflect the local population. The aim of this study was to determine if age-adjusted reference ranges for serum free light chains would have implications for demand management of further laboratory investigations including immunofixation. Methods After certain exclusions, 4293 samples from individuals seen in primary care across Oxfordshire between 2014 and 2016 were identified for analysis of patient characteristics, serum free light chain results and estimated glomerular filtration rate. Results We found age to be an independent variable when considering serum free light chain concentrations, ratio and estimated glomerular filtration rate. The reference ranges derived from our data differ markedly from the original Binding Site ranges. When the age-specific ranges are retrospectively applied to our population, there is a 38% decrease in follow-up testing with no loss of specificity. Conclusion We feel confident implementing new age-specific serum free light chain reference ranges in our laboratory. We have developed a simple algorithm for evaluating serum free light chains based on age and estimated glomerular filtration rate. We encourage laboratories to establish their own local reference ranges using large cohorts and their chosen serum free light chain assay platform.

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