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Test ID: PBLI Plasma Cell Assessment, Blood

Reporting Name

Plasma Cell Assessment, B

Useful For

Detecting peripheral blood involvement by plasma cell proliferative disorders

 

Establishing the diagnosis of and determining prognosis for plasma cell proliferative disorders

Testing Algorithm

The following algorithms are available:

-Amyloidosis: Laboratory Approach to Diagnosis

-Multiple Myeloma: Laboratory Screening

Specimen Type

Whole blood


Shipping Instructions


Specimen must arrive within 72 hours of collection.



Necessary Information


Date and time of collection are required.



Specimen Required


Container/Tube:

Preferred: Green top (sodium heparin)

Acceptable: Lavender top (EDTA)

Specimen Volume: 10 mL

Collection Instructions:

1. Do not centrifuge.

2. Send whole blood specimen in original tube. Do not aliquot.


Specimen Minimum Volume

4 mL

Specimen Stability Information

Specimen Type Temperature Time Special Container
Whole blood Ambient (preferred) 72 hours
  Refrigerated  72 hours

Reference Values

An interpretive report will be provided.

Day(s) Performed

Specimens processed: Monday through Sunday

Results reported: Monday through Friday

Test Classification

This test was developed using an analyte specific reagent. Its performance characteristics were determined by Mayo Clinic in a manner consistent with CLIA requirements. This test has not been cleared or approved by the US Food and Drug Administration.

CPT Code Information

88184-Flow cytometry, cell surface, cytoplasmic

88185 x 5-Each additional marker

88187-Flow cytometry, interpretation; 2 to 8 markers

LOINC Code Information

Test ID Test Order Name Order LOINC Value
PBLI Plasma Cell Assessment, B 86900-8

 

Result ID Test Result Name Result LOINC Value
30388 Blood Plasma Cell Light Chain 86900-8
26838 # Monotypic PCs per 150,000 events 19099-1
26839 PC Event Interpretation 69052-9

Clinical Information

Plasma cell proliferative disorders are a group of hematologic neoplasms, all of which are derived from clonal plasma cells. These disorders exhibit a wide range of biologic activity ranging from monoclonal gammopathy of uncertain significance, a usually indolent disorder with a low rate of disease progression, to multiple myeloma, a disease that most often is aggressive with poor long-term survival. Detecting plasma cell immunoglobulin light chain restriction (ie, the presence of either predominately kappa or predominately lambda light chains) is an important element in assessing plasma cell clonality and, hence, establishing the diagnosis. Furthermore, a greater degree of peripheral blood involvement by these disorders is associated with more aggressive disease types and, therefore, is an adverse prognostic indicator.

 

Flow cytometric immunophenotyping (FCIP) is a recognized method for detecting plasma cell immunoglobulin light chain restriction. However, short comings of the traditionally performed technique include relative insensitivity and consistent underestimation of the number of clonal plasma cells present. Both short comings are likely attributable to limitations of the instruments and antibodies used, as well as the presence of intraclonal phenotypic heterogeneity, which creates difficulties in accurately detecting and enumerating all of the clonal plasma cells. For this reason, the FCIP plasma cell clonality assessment previously performed in our laboratory was supplemented with a slide-based immunofluorescence technique.

 

However, recent advances in flow cytometry have led to the development of more powerful instruments and antibody reagents that allow for the use of greater antibody combinations and increased resolution of the data. With these tools, the ability of FCIP to detect and enumerate plasma cell clones has been greatly enhanced, allowing us to discontinue the supplemental, labor-intensive, slide-based plasma cell evaluation in peripheral blood specimens.

 

The following algorithms are available:

-Amyloidosis: Laboratory Approach to Diagnosis

-Multiple Myeloma: Laboratory Screening

Interpretation

In normal peripheral blood specimens, no clonal plasma cells are present (polytypic or too few to detect).

 

Plasma cells are CD38 and CD138 positive.

 

Normal (polyclonal, nonneoplastic) plasma cells are typically CD19-positive, whereas neoplastic (clonal) plasma cells typically are CD19-negative. CD19 expression is especially helpful in distinguishing clonal from nonclonal plasma cells when few analyzable cells are present.

 

CD45 may be expressed by both normal and neoplastic plasma cells. In some plasma cell proliferative disorders there are both CD45-positive and CD45-negative subsets within the clonal cell population.

 

The evaluation of these antigens aids in the identification of abnormal plasma cells, however, they will not be reported independently.

Clinical Reference

1. Chakraborty R, Muchtar E, Kumar SK, et al: Risk stratification in myeloma by detection of circulating plasma cells prior to autologous stem cell transplantation in the novel agent era. Blood Cancer J. 2016 Dec;6(12):e512. doi: 10.1038/ bcj.2016.117

2. Chakraborty R, Muchtar E, Kumar SK, et al: Serial measurements of circulating plasma cells before and after induction therapy have an independent prognostic impact in patients with multiple myeloma undergoing upfront autologous transplantation. Haematologica. 2017 Aug;102(8):1439-1445

3. Evans LA, Jevremovic D, Nandakumar B, et al: Utilizing multiparametric flow cytometry in the diagnosis of patients with primary plasma cell leukemia. Am J Hematol. 2020 Jun;95(6):637-642. doi: 10.1002/ajh.25773

4. Gonsalves WI, Jevremovic D, Nandakumar B, et al: Enhancing the R-ISS classification of newly diagnosed multiple myeloma by quantifying circulating clonal plasma cells. Am J Hematol. 2020 Mar;95(3):310-315. doi: 10.1002/ajh.25709

5. Ravi P, Kumar SK, Roeker L, et al. Revised diagnostic criteria for plasma cell leukemia: results of a Mayo Clinic study with comparison of outcomes to multiple myeloma. Blood Cancer J. 2018 Nov;8(12):116

Report Available

1 to 2 days

Method Name

Flow Cytometry

Forms

If not ordering electronically, complete, print, and send a Hematopathology/Cytogenetics Test Request (T726) with the specimen.

Mayo Clinic Laboratories | Hematology Catalog Additional Information:

mml-myeloma-amyloidosis-dysprotenemia