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Test Name:
ZAP-70, by Flow Cytometry
- SBMF No:
36143 - Performance Lab Name:
Flow Cytometry/Molecular Pathology - Test Mnemonic:
ZAP70 - ABN:
Not required - CPT Code:
88184; 88185x4; 88187 - LOINC Code:
46232-5; 59465-5 - Also Known As:
Zeta-Chain-Associated Protein Kinase 70 - Also See:
36135 Chronic Lymphocytic Leukemia Panel, by FISH
25219 Leukemia/Lymphoma Immunophenotyping, by Flow Cytometry, Blood or Bone Marrow - Spec Type:
Bone marrow - Spec Container:
Lavender top (EDTA) or pale yellow top (ACD) tube - Alt Spec Type:
Whole blood - Alt Spec Container:
Lavender top (EDTA) or pale yellow top (ACD) tube - Pref Vol:
5.0 mL - Min Vol:
1.0 mL - Fasting:
No - Spec Collect:
Routine venipuncture - Spec Process:
Mix contents of collection tube gently, but well
Do not centrifuge
Do not remove plasma from cells
Do not refrigerate or freeze - Spec Store Transport:
Room temperature - Spec Stability:
- 24 hours room temperature (20-30°C)
- Note: Must be analyzed within 24 hours of collection
- Refrigerated (2-8°C): Unacceptable
- Frozen (-20°C): Unacceptable
- Spec Reject:
Frozen, hemolyzed or clotted sample - Methodology:
Flow Cytometry - Use:
ZAP-70 (Zeta-chain-associated protein kinase 70) can be used as a marker for a subpopulation of B-cell Chronic Lymphocytic Leukemia (CLL) patients with a more aggressive clinical course and a shorter overall mean survival.
Expression of ZAP-70 can be used as an indication for treatment in these patients. - Clinical Significance:
ZAP-70 is an enzyme that is normally expressed in T-lymphocytes and is critical for T-cell activation. The clinical course of B-cell CLL is variable. Most patients generally experience a long mean survival time of up to 25 years. However, 20-30% of low stage patients experience early disease progression with a decreased mean survival of 8-10 years. It has been shown that mutated vs. unmutated (germline) immunoglobulin variable heavy chain gene status is highly predictive of clinical outcome. CLL lymphocytes with unmutated immunoglobulin heavy chain genes are seen in patients in the poorer survival category, while patients with mutated IgVH genes have the usual longer median survival. It has been shown that strong expression of ZAP-70 is usually associated with those cases having unmutated (germline) IgVH genes. Although the presence of an unmutated IgVH gene is strongly associated with the expression of ZAP-70, some studies have shown that ZAP-70 is an even stronger predictor of the need for treatment in B-cell CLL compared to gene mutation status. - Reference Range:
Positive Cut-Off for ZAP-70: 20% or greater - Additional Test Info:
ZAP-70 is added as an additional marker depending upon the test results of Leukemia/Lymphoma Immunophenotyping by Flow Cytometry (SBMF test #25219).
Positive ZAP-70 in chronic lymphocytic leukemia usually correlates with unmutated IgVH and more aggressive disease. However, negative ZAP -70 does not completely rule out unmutated IgVH or more aggressive disease.
Also consider: Chronic Lymphocytic Leukemia Panel by FISH (SBMF #36135) – see Technical Notice, May 2006. - Day Run:
As received - Time Run:
9:00 am - Time Reported:
24 hours - Test Type:
FLOW
