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HelpTest ID ZAP70 ZAP-70, Chronic Lymphocytic Leukemia (CLL) Prognosis
Useful For
Assessing a risk factor for disease progression in patients with B-cell chronic lymphocytic leukemia
Additional Tests
| Test ID | Reporting Name | Available Separately | Always Performed |
|---|---|---|---|
| FCINT | Flow Cytometry Interp, 2-8 Markers | No, (Bill Only) | Yes |
Testing Algorithm
When this test is ordered, flow cytometry interpretation, 2 to 8 markers will always be performed at an additional charge.
Method Name
Immunophenotyping
Reporting Name
ZAP-70Specimen Type
Whole Blood ACD-BSpecimen must arrive within 72 hours of draw.
Container/Tube: Yellow top (ACD)
Specimen Volume: 6 mL
Collection Instructions: Specimen must be refrigerated within 9 hours of draw.
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
5 mL
Specimen Stability Information
| Specimen Type | Temperature | Time |
|---|---|---|
| Whole Blood ACD-B | Refrigerated | 72 hours |
Clinical Information
B-cell chronic lymphocytic leukemia (CLL) is the most common leukemia in adults. Its clinical course is highly variable with survival times ranging from months to decades. The standard procedure for estimating prognosis is clinical staging systems developed by Rai and Binet. In these staging systems, most CLL patients have early-stage disease. Genetic prognostic markers such as immunoglobulin heavy chain gene mutational status and FISH studies for specific chromosomal abnormalities have now been developed to refine the risk of progressive disease. CD38 and ZAP-70 have been identified as surrogate markers for mutation status and can be evaluated by flow cytometric immunophenotyping.
ZAP-70 (70-kDa zeta-associated protein) is an intracellular tyrosine kinase discovered initially because of its role in T-cell signaling. It has also been found to be associated with the B-cell receptor in CLL. The expression of ZAP-70 (≥20% of B cells) has been associated with an increased risk for an adverse outcome in B-cell CLL and is considered an important risk factor in these patients. ZAP-70 expression, if present, is constant throughout the patient's clinical course and thus is a valid risk marker regardless of when it is evaluated.
Reference Values
An interpretive report will be provided.
Cautions
ZAP-70 is an intracellular activation marker in chronic lymphocytic leukemia (CLL) cells and expression can be labile after 24 hours. Failure to follow specimen processing, transportation, and storage requirements may lead to false results.
Bone marrow, lymph node, and tissue specimens will not be accepted as these specimen types have not been clinically validated at Mayo or in literature studies. Since B-cell CLL is, by definition, a peripheral leukemic process and since blood specimens can be easily obtained, this should not be a significant limitation.
A ZAP-70 study may be rejected if the histogram pattern indicates that there have been any cellular changes that could prevent accurate interpretation of antigen expression.
Day(s) Performed
Specimens are processed Monday through Sunday and reported Monday through Friday.
Report Available
3 daysPerforming 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 x 1-Flow cytometry; first cell surface, cytoplasmic or nuclear marker
88185 x 2–Flow cytometry; additional cell surface, cytoplasmic or nuclear marker (each)
88187–Flow cytometry interpretation, 2 to 8 Markers