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Test Code SZDIA Sezary Diagnostic Flow Cytometry, Blood

Secondary ID

64750

Useful For

Identifying phenotypically aberrant T-cell population in peripheral blood as part of the diagnostic workup for Sezary syndrome

 

Roughly assessing the circulating tumor burden in mycosis fungoides, if the phenotype of the neoplastic cells is distinctive enough

Additional Tests

Test ID Reporting Name Available Separately Always Performed
FIRST Flow Cytometry, Cell Surface, First No Yes
ADD1 Flow Cytometry, Cell Surface, Addl No Yes

Reflex Tests

Test ID Reporting Name Available Separately Always Performed
FCIMS Flow Cytometry Interp, 9-15 Markers No No
FCINS Flow Cytometry Interp,16 or greater No No
VBETA TCR V-BETA No No

Testing Algorithm

Sezary panel is ordered in cases of suspected Sezary syndrome or cutaneous T-cell lymphoma with peripheral blood involvement. For cases without a previously confirmed diagnosis of Sezary syndrome, a triage panel will also be performed to exclude a B-cell lymphoproliferative disorder. If there is a significant phenotypically distinct T-cell population detected, a V-beta panel for proof of clonality may be ordered by signing pathologist.

 

A triage panel is always performed. The panel is charged based on number of markers tested (FIRST for first marker, ADD1 for each additional marker). In addition, reflex testing may occur to fully characterize a disease state or clarify any abnormalities from the screening test. Reflex tests will be performed at an additional charge for each marker tested (ADD1 if applicable).

Method Name

Immunophenotyping

Reporting Name

Sezary Diagnostic Flow Cytometry, B

Specimen Type

Whole blood


Specimen Required


Specimen Type: Blood

Collection Container/Tube:

Preferred: Yellow top (ACD)

Acceptable: EDTA, Heparin

Specimen Volume: 6 mL

Collection Instructions:

1. Do not transfer blood to other containers.

2. Label specimen as blood.

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

(http://www.mayomedicallaboratories.com/it-mmfiles/hematopathology-request-form.pdf)


Specimen Minimum Volume

1 mL

Specimen Stability Information

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

Reject Due To

Hemolysis

Mild OK; Gross reject

Lipemia

Mild OK; Gross OK

Icterus

NA

Other

NA

Clinical Information

Sezary syndrome is a leukemic form of cutaneous T-cell lymphoma (CTCL). By definition, it is associated with systemic skin involvement (erythroderma) and the presence of at least 1000/microL of circulating cells with irregular nuclear features (Sezary cells). Morphologic assessment of the number of Sezary cells has been proven to have low reproducibility. Therefore, WHO/European Organization for Research and Treatment of Cancer (EORTC) classification of skin tumors adopted alternative methods to assess circulating T-cells in order to establish the diagnosis of Sezary syndrome. These include CD4:CD8 ratio of more than 10:1, and selective loss of CD7 and/or CD26 on 40% and 30% of the CD4-positive cell population, respectively. It is important to recognize that the later criteria (fulfilled by peripheral blood flow cytometry immunophenotyping) are relative, and not in direct correlation with absolute counts of Sezary cells defined by morphology.

Reference Values

An interpretive report will be provided. This test will be processed as a laboratory consultation. An interpretation of the immunophenotypic findings and, if available, morphologic features will be provided by a board-certified hematopathologist for every case.

Interpretation

Sezary cells typically show loss of CD7 and/or CD26. As loss of these markers is not completely sensitive or specific for Sezary cells, and there are circulating normal CD4-positive T-cells, which usually cannot be excluded from the analysis, the WHO/European Organization for Research and Treatment of Cancer (EORTC) classification of skin tumors proposed cutoffs of 30% for CD26 loss and 40% for CD7 loss on CD4-positive T-cells as diagnostic criteria for Sezary syndrome. In addition, a CD4:CD8 ratio of greater than or equal to 10:1 in a gated T-cell population is also considered abnormal and part of the diagnostic algorithm for Sezary syndrome.

 

In mycosis fungoides staging studies the cutoffs are even less clearly defined. The clinical outcome was worse in patients with more than 5% of circulating lymphocytes showing Sezary-like morphology. However, flow cytometry immunophenotyping is deemed useful for relative quantification of these cells only if they can be separated by aberrant expression of other surface markers. In majority of cases, this cannot be accomplished to the proposed cutoff point (5% of circulating lymphocytes).

 

The test will be resulted as "No phenotypically aberrant T-cell population detected" if there is no specific phenotype that allows separation of potentially abnormal CD4-positive T-cells, loss of CD26 (and/or CD7) is present in less than 30% (40%), and CD4:CD8 ratio is less than 10:1. If any of the above aberrancies are present, the test will be resulted as "Phenotypically distinct T-cell population is detected" with a description of phenotype, percentage of total CD4-positive population, and percentage of total analyzed events. In addition, the phenotype will be compared to that of any distinct T-cell population previously seen in the same patient by our laboratory.

Clinical Reference

1. Honra P, Deaver DM, Qin D, et al: Quantitative flow cytometric identification of aberrant T cell clusters in erythrodermic cutaneous T cell lymphoma: Implications for staging and prognosis. J Clin Pathol 2014;67:431-436

2. Vaughan J, Harrington AM, Hari PN, et al: Immunophenotypic stability of Sezary cells by flow cytometry: usefulness of flow cytometry in assessing response to and guiding alemtuzumab therapy. Am J Clin Pathol 2012 Mar;137(3):403-411

3. Kelemen K, Guitart J, Kuzel TM, et al: The usefulness of CD26 in flow cytometric analysis of peripheral blood in Sezary syndrome. Am J Clin Pathol 2008 Jan;129(1):146-156

4. Wilcox RA: Cutaneous T-cell lymphoma: 2016 update on diagnosis, risk-stratification, and management. Am J Hematol 2016;91:152-165; doi: 10.1002/ajh.24233

5. Olsen E, Vonderheid E, Pimpinelli N, et al: Revisions to the staging and classification of mycosis fungoides and Sezary syndrome: a proposal of the International Society for Cutaneous Lymphomas (ISCL) and the cutaneous lymphoma task force of the European Organization of Research and Treatment of Cancer (EORTC). Blood 2007 Sep 15;110(6):1713-1722

6. Willemze R, Jaffe ES, Burg G, et al: WHO-EORTC classification for cutaneous lymphomas. Blood 2005;105:3768-3785

Day(s) and Time(s) Performed

Specimens are processed Monday through Sunday and reported Monday through Saturday.

Analytic Time

1 day

Performing Laboratory

Mayo Medical Laboratories in Rochester

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 U.S. Food and Drug Administration.

CPT Code Information

88184-Flow cytometry; first cell surface, cytoplasmic or nuclear marker x 1

88185-Flow cytometry; additional cell surface, cytoplasmic or nuclear marker (each)

88188-Flow Cytometry Interpretation, 9 to15 Markers (if appropriate)

88189-Flow Cytometry Interpretation, 16 or More Markers (if appropriate)

LOINC Code Information

Test ID Test Order Name Order LOINC Value
SZDIA Sezary Diagnostic Flow Cytometry, B In Process

 

Result ID Test Result Name Result LOINC Value
CK126 Sezary Diagnostic In Process
CK127 Final Diagnosis In Process
CK128 Special Studies 30954-2
CK129 Microscopic Description 22635-7