Combined analysis using extended renal reference range of serum free light chain ratio and serum protein electrophoresis improves the diagnostic accuracy of multiple myeloma in renal insufficiency

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.

Laboratory Detection and Initial Diagnosis of Monoclonal Gammopathies

CONTEXT.—

The process for identifying patients with monoclonal gammopathies is complex. Initial detection of a monoclonal immunoglobulin protein (M protein) in the serum or urine often requires compilation of analytical data from several areas of the laboratory. The detection of M proteins depends on adequacy of the sample provided, available clinical information, and the laboratory tests used.

OBJECTIVE.—

To develop an evidence-based guideline for the initial laboratory detection of M proteins.

DESIGN.—

To develop evidence-based recommendations, the College of American Pathologists convened a panel of experts in the diagnosis and treatment of monoclonal gammopathies and the laboratory procedures used for the initial detection of M proteins. The panel conducted a systematic literature review to address key questions. Using the Grading of Recommendations Assessment, Development, and Evaluation approach, recommendations were created based on the available evidence, strength of that evidence, and key judgements as defined in the Grading of Recommendations Assessment, Development, and Evaluation Evidence to Decision framework.

RESULTS.—

Nine guideline statements were established to optimize sample selection and testing for the initial detection and quantitative measurement of M proteins used to diagnose monoclonal gammopathies.

CONCLUSIONS.—

This guideline was constructed to harmonize and strengthen the initial detection of an M protein in patients displaying symptoms or laboratory features of a monoclonal gammopathy. It endorses more comprehensive initial testing when there is suspicion of amyloid light chain amyloidosis or neuropathies, such as POEMS (polyneuropathy, organomegaly, endocrinopathy, M protein, and skin changes) syndrome, associated with an M protein.

Optimización de flujos de trabajo y paneles de cribado para la detección de gammapatias monoclonales malignas

Objetivos

El mieloma múltiple (MM) es una de las malignidades hematológicas con más retraso en el diagnóstico. Frecuentemente, llegan al laboratorio peticiones de técnicas de detección de MM sin sospecha específica generando mucha carga de trabajo y baja eficiencia. Objetivo: aumentar la eficiencia de aplicación de los protocolos de cribado del MM.

Métodos

Recopilación de resultados de electroforesis (EPS) e inmunofijación en suero (IFS) y orina (IFO), y de cadenas ligeras libres en suero (CLLS) de 75 pacientes de MM al diagnóstico, 3 amiloidosis y un plasmocitoma solitario. Recopilamos las alteraciones analíticas presentes en estos pacientes vs población control (n.=120). Validación del algoritmo de cribado en 261 pacientes consecutivos con sospecha clínica o analítica de MM.

Resultados

Algoritmos de cribado más sensibles: EPS + CLLS o IFS + CLLS (98% de sensibilidad). Prospectivamente, el protocolo EPS + CLLS detectó 27 de las 28 gammapatia monoclonal (GM) diagnosticadas y ahorró 15 h laborales. Frecuencia de resultados analíticos alterados, 5 de los 6 parámetros eran más frecuentes en el grupo a estudio, acumulando ≥3 parámetros alterados el 61,1% vs. el 1,7% de la población control (Valor predictivo positivo: 85%; Valor predictivo negativo: 94%).

Conclusiones

El protocolo de cribado EPS + CLLS fue el más sensible y menos laborioso. Además, permitió mejorar la sensibilidad diagnóstica y la eficiencia de trabajo.

Optimization of workflow and screening panels for the detection of malignant monoclonal gammopathies

Objectives

Multiple myeloma (MM) is one of the hematologic malignancies with a greater delay in diagnosis. Laboratories receive numerous MM screening test requests without a specific suspicion, which entails a substantial workload and reduces the efficiency of laboratories. Objective: to increase the efficacy of MM screening protocols.

Methods

The results of serum protein electrophoresis (SPEP), serum protein immunofixation electrophoresis (SIFE), urine protein immunofixation electrophoresis, and serum free light chain assays of 75 patients with MM, three with amyloidosis, and a patient with solitary plasmocytoma were collected. The frequency of a set of biochemical alterations in these patients was compared with that in controls (n=120). A validation of the screening algorithm was carried out in 261 consecutive patients with a clinical or analytical suspicion of MM.

Results

SPEP+SFLC or SIFE+SFLC (98% sensitivity) were the screening algorithms with the highest sensitivity. Prospectively, the SPEP + SFLC detected 27 of the 28 confirmed cases of MG and saved 15 h of work. Alterations in five of the six parameters studied were more frequent in the study group, with a cumulative value of ≥3 parameters altered (61.1 vs. 1.7%) (positive predictive value: 85%; negative predictive value: 94%).

Conclusions

The SPEP+SFLC screening protocol demonstrated the highest sensitivity and was the least time-consuming protocol. In addition, this protocol improves diagnostic sensitivity and laboratory performance.

Diagnostic performances of M-protein tests according to the clinical presentations of kidney disease

BACKGROUND

Screening for monoclonal immunoglobulin (MIg) is critical in patients with kidney disease.

METHODS

We identified 943 subjects who underwent kidney biopsy and at least one of monoclonal (M)-protein tests (serum and urine electrophoresis [EP], serum and urine immunofixation [IF], and serum free light chain [FLC] ratio). The sensitivities of several combinations of the 5 tests were examined by clinical presentations of kidney disease.

RESULTS

The sensitivities of serum EP, urine EP, and the serum FLC ratio were 65%, 68%, and 71%, respectively, which were lower than those of serum IF (79%) and urine IF (87%) to detect MIg. In the nephrotic syndrome (NS) group, the panel including serum IF, urine IF, and the serum FLC ratio exhibited 100% sensitivity to identify MIg in patients with multiple myeloma (MM) or with monoclonal gammopathy of renal significance (MGRS). In subjects without NS, the panel of serum EP and serum FLC ratio detected MIg in all cases of MM, and the serum IF plus serum FLC ratio detected MIg in all cases of MGRS.

CONCLUSION

This study demonstrated that the sensitivity of screening panels differed by the presenting features of kidney disease. The M-protein tests had lower sensitivity for detection of MIg in subjects with NS compared to those with other clinical presentation.