Audit of Use and Overuse of Serum Protein Immunofixation Electrophoresis and Serum Free Light Chain Assay in Tertiary Health Care: A Case for Algorithmic Testing to Optimize Laboratory Utilization

Understanding the Constraints and Optimization of Serum Immunofixation Electrophoresis and Serum Free Light Chains for Detecting Monoclonal Proteins: A Single-Center Experience

Introduction  Serum immunofixation electrophoresis (SIFE) and serum free light chain (SFLC) assay are imperative investigations in diagnosis and follow-up of multiple myeloma (MM). SFLC assays are reported to have higher sensitivity than SIFE. However, discrepancies have been reported between them. The current study was aimed at assessing concordance and discordance between SIFE and SFLC results in MM. Methods  A total of 450 observations of both SIFE and SFLC were obtained from treatment-naive and follow-up MM patients. Results  One hundred and twenty-nine (28.7%) values were observed as discordant, that is, positive SIFE with normal SFLC ratio or negative SIFE with abnormal SFLC ratio ( p -value < 0.00001). Proportion of discordance was higher in SIFE positive-SFLC normal cases than SIFE negative-SFLC abnormal cases. Discordance was more frequent in follow-up cases. Conclusion  Negative SFLC alone may not be reliable for MM follow-up. Algorithm may be based on SFLC measurements on each follow-up till attainment of normal SFLC ratio. Once SFLC normalizes, follow-up may be done with SIFE. If SIFE is positive, further follow-up with SIFE may be initiated.

Use of Clinical Decision Support to Improve the Laboratory Evaluation of Monoclonal Gammopathies

OBJECTIVES

There is considerable variation in ordering practices for the initial laboratory evaluation of monoclonal gammopathies (MGs) despite clear society guidelines to include serum free light chain (sFLC) testing. We assessed the ability of a clinical decision support (CDS) alert to improve guideline compliance and analyzed its clinical impact.

METHODS

We designed and deployed a targeted CDS alert to educate and prompt providers to order an sFLC assay when ordering serum protein electrophoresis (SPEP) testing.

RESULTS

The alert was highly effective at increasing the co-ordering of SPEP and sFLC testing. Preimplementation, 62.8% of all SPEP evaluations included sFLC testing, while nearly 90% of evaluations included an sFLC assay postimplementation. In patients with no prior sFLC testing, analysis of sFLC orders prompted by the alert led to the determination that 28.9% (800/2,769) of these patients had an abnormal κ/λ ratio. In 452 of these patients, the sFLC assay provided the only laboratory evidence of a monoclonal protein. Moreover, within this population, there were numerous instances of new diagnoses of multiple myeloma and other MGs.

CONCLUSIONS

The CDS alert increased compliance with society guidelines and improved the diagnostic evaluation of patients with suspected MGs.

Engaging Pathology Residents in Clinical Chemistry: The Essential Ingredient Is a Committed Teacher

BACKGROUND

Pathology residents are thought to show a lack of interest in clinical chemistry, therefore potentially graduating from training programs unprepared to function as laboratory directors and clinical consultants.

METHODS

A structured program of tutorials based primarily on Henry's textbook, supplemented by recent review articles; a question bank of about 600 questions to emphasize key concepts; requirement for performing and presenting quality improvement projects; participation in on-site CAP inspections; review of reference laboratory test requests; and involving residents in scholarly activity have resulted in sustained, transferable, and significant improvements in engagement, knowledge, competence, and examination scores.

RESULTS

The primary parameter for measuring change in resident competence and engagement were improvements in resident in-service examination (RISE) scores, publications in peer-reviewed journals, and receipt of awards. The revised program produced significant improvement in RISE scores in clinical chemistry, over and above the improvements in the general residency program. The residents were authors on 12 publications in peer-reviewed PubMed listed journals in the 5-year period since revision in the clinical chemistry curriculum compared to no publications in clinical chemistry in the 5-year period before the new curriculum. Over the past 2 years, 6 of the 11 publications by graduating residents were in clinical chemistry, and 6 of 7 awards for research were garnered by residents engaged in clinical chemistry investigations. All of the residents passed their clinical pathology boards on first attempt since the change compared to 2 failures in the prior 5-year period.

CONCLUSIONS

The structured program described here is important as a template that could be adopted by any pathology training program. The question bank developed by this program is a valuable and transferable aid. However, success of such a program is dependent on the commitment of a knowledgeable, dedicated, and passionate teacher.

Serum and Urine Protein Electrophoresis and Serum-Free Light Chain Assays in the Diagnosis and Monitoring of Monoclonal Gammopathies

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.

Validation and Implementation of an Ordering Alert to Improve the Efficiency of Monoclonal Gammopathy Evaluation

OBJECTIVES

To evaluate the use of a provider ordering alert to improve laboratory efficiency and reduce costs.

METHODS

We conducted a retrospective study to assess the use of an institutional reflex panel for monoclonal gammopathy evaluation. We then created a clinical decision support (CDS) alert to educate and encourage providers to change their less-efficient orders to the reflex panel.

RESULTS

Our retrospective analysis demonstrated that an institutional reflex panel could be safely substituted for a less-efficient and higher-cost panel. The implemented CDS alert resulted in 79% of providers changing their high-cost order panel to an order panel based on the reflex algorithm.

CONCLUSIONS

The validated decision support alert demonstrated high levels of provider acceptance and directly led to operational and cost savings within the laboratory. Furthermore, these studies highlight the value of laboratory involvement with CDS efforts to provide agile and targeted provider ordering assistance.

Serum Free Light Chain Assay in Monoclonal Gammopathic Manifestations

Background

Serum free light chain assay is used in the diagnosis and monitoring of monoclonal gammopathic manifestations. For the kappa (κ)/lambda (λ) ratio, there is a 36% false-positive rate in patients without monoclonal gammopathic manifestations and a 30% false-negative rate in patients with monoclonal gammopathic manifestations. This study was undertaken to address the higher false-negative rate in λ chain–associated monoclonal lesions.

Methods

Results of serum protein electrophoresis, serum immunofixation electrophoresis, and serum free light chain assays were reviewed retrospectively. The results for serum free light chains in cases of intact immunoglobulin monoclonal gammopathic manifestations only were analyzed.

Results

Concentrations of involved serum free light chains were significantly higher in κ chain–associated lesions than in λ chain–associated lesions. The concentration of uninvolved light chains was significantly higher in λ chain–associated lesions.

Conclusions

κ light chains are present in significantly greater abundance than are λ chains in their respective monoclonal lesions. Moreover, κ and λ light-chain levels are not comparable for similar quantitative levels of monoclonal immunoglobulins. The findings warrant a reconsideration of the role of serum free light chain concentrations and involved to uninvolved serum free light chain ratio in designation of myeloma-defining conditions and other diagnostic criteria based on serum free light chain assay.

Oligoclonal Pattern/Abnormal Protein Bands in Post-Treatment Plasma Cell Myeloma Patients: Implications for Protein Electrophoresis and Serum Free Light Chain Assay Results

BACKGROUND

The impact of autologous stem cell transplantation (ASCT) in plasma cell myeloma patients on the frequency, quality, and timing of oligoclonal pattern in serum protein electrophoresis/immunofixation electrophoresis (SPEP/SIFE) and serum free light chain assay (SFLCA) was evaluated.

METHODS

Laboratory results and clinical data for 251 patients with plasma cell myeloma, who had SPEP/SIFE and/or SFLCA performed between January 2010 and December 2016 were reviewed. The results for SPEP/SIFE and SFLCA were compared in patients with ASCT to those without ASCT. The implications of oligoclonal pattern in interpretation of SPEP/SIFE and SFLCA - κ/λ ratio were addressed.

RESULTS

In 251 patients, a total of 3,134 observations, of either SPEP/SIFE and/or SFLCA, were reviewed. One hundred fifty-nine patients received ASCT. The incidence of oligoclonal patterns was significantly higher after ASCT. More than half of the oligoclonal patterns developed in the first year after transplantation. In 13 of the 84 patients with lambda chain restricted plasma cell myeloma, the κ/λ ratio was kappa dominant in the presence of oligoclonal pattern. There was no reversal of κ/λ ratio in patients with kappa chain restricted plasma cell myelomas.

CONCLUSIONS

ASCT is associated with significantly higher incidence of oligoclonal patterns than with chemotherapy alone. The presence of oligoclonal patterns has the potential to interfere with the interpretation of SPEP/SIFE and ascertainment of complete remission. At a minimum, the oligoclonal pattern caused an incorrect kappa dominant κ/λ ratio in 15.5% of patients with lambda chain restricted plasma cell myeloma. If a similar rate were to be applied to the 167 kappa chain myeloma patients, about 26 of these would have displayed an erroneous kappa chain dominant κ/λ ratio. The presence of oligoclonal pattern further degrades the performance of already dubious SFLCA. The need for recording the location of monoclonal spike in SPEP/SIFE and higher resolution protein electrophoresis methods are highlighted.

Location of monoclonal peak as a tool in checking specimen integrity

OBJECTIVES

Serum protein electrophoresis is a commonly used test in the diagnosis and follow-up of patients with monoclonal gammopathies. The practice of documenting the location of the peak may serve as delta check flags in SPEP samples.

METHODS

We report on the inconsistent finding on two tests performed about three months apart. The inconsistency was discovered due to recognition of the change in the location of the monoclonal immunoglobulin on protein electrophoresis.

RESULTS

Repeat testing with a third specimen revealed that the first test was run on a wrong specimen.

CONCLUSION

Recording the location of the monoclonal spike is recommended to serve as an additional "delta" check.

Serum Free Light Chain Assay and κ/λ Ratio: Performance in Patients With Monoclonal Gammopathy-High False Negative Rate for κ/λ Ratio

Background

Serum free light chain assay (SFLCA) and κ/λ ratio, and protein electrophoretic methods are used in the diagnosis and monitoring of monoclonal gammopathies.

Methods

Results for serum free light chains, serum and urine protein electrophoreses and immunofixation electrophoreses in 468 patients with a diagnosis of monoclonal gammopathy were compared. The results of the two methods were graded as concordant, non-concordant or discordant with the established diagnoses to assess the relative performance of the methods. Results of κ/λ ratio in samples with monoclonal protein detectable by electrophoretic methods were also analyzed.

Results

Protein electrophoreses results were concordant with the established diagnoses significantly more often than κ/λ ratio. The false negative rate for κ/λ ratio was higher than that for electrophoretic methods. κ/λ ratio was falsely negative in about 27% of the 1,860 samples with detectable monoclonal immunoglobulin. The false negative rate was higher in lesions with lambda chains (32%) than those with kappa chains (24%). The false negative rate for κ/λ ratio was over 55% in samples with monoclonal gammopathy of undetermined significance. Even at first encounter, the false negative rates for κ/λ ratios for monoclonal gammopathy of undetermined significance, smoldering myeloma and multiple myeloma were 66.98%, 23.08%, and 30.15%, respectively, with false negative rate for lambda chain lesions being higher.

Conclusions

Electrophoretic studies of serum and urine are superior to SFLCA and κ/λ ratio. Abnormal κ/λ ratio, per se, is not diagnostic of monoclonal gammopathy. A normal κ/λ ratio does not exclude monoclonal gammopathy. False negative rates for lesions with lambda chain are higher than those for lesions with kappa chains. Electrophoretic studies of urine are underutilized. Clinical usefulness and medical necessity of SFLCA and κ/λ ratio is of questionable value in routine clinical testing.

Serum Free Light Chain Assay and κ/λ Ratio Performance in Patients Without Monoclonal Gammopathies: High False-Positive Rate

OBJECTIVES

Serum free light chain assay is a recommended screening test for monoclonal gammopathies. Anecdotal observations indicated a high rate of false-positive abnormal κ/λ ratios. This study was undertaken to ascertain the magnitude of the false-positive rate and factors contributing to the error rate.

METHODS

Results of serum protein electrophoresis, serum free light chains, and related tests, usually done for investigation of suspected monoclonal gammopathy, were reviewed retrospectively for 270 patients and 297 observations.

RESULTS

Using the conventional κ/λ ratio, 36.4% of the ratios were abnormal, in the absence of monoclonal gammopathy. When the renal κ/λ ratio was used, the rate of abnormal κ/λ ratios was 30.1%. In patients with a γ-globulin concentration of 1.6 g/dL or more, the usual κ/λ ratio was abnormal in 54.8% of the patients. Urine protein electrophoresis was used in 53 (19.6%) instances, whereas bone marrow examination was done in 65 (24.1%) cases.

CONCLUSIONS

Usual κ/λ ratio was abnormal in 36.4% of the observations in patients without evidence of monoclonal gammopathy, and an abnormal κ/λ ratio should not be used as the sole indicator for diagnosis of neoplastic proliferation of the lympho-plasmacytic system. Hypergammaglobulinemia is associated with a higher rate of false-positive abnormal κ/λ ratios. Examination of urine for monoclonal immunoglobulins may be underused, and recommendations by some to use serum free light chain assay in place of, rather than as an adjunct to, urine electrophoresis are not warranted.