FISH, Myeloproliferative Neoplasms (MPN) (Eosinophilia)

Test Code
90665


CPT Codes
88271 (x7), 88275 (x3)

Preferred Specimen
3 mL bone marrow or 5 mL whole blood collected in a sodium heparin (green-top) tube


Minimum Volume
1 mL bone marrow • 3 mL whole blood


Other Acceptable Specimens
Bone marrow collected in: Transport medium, sodium heparin (dark/royal blue-top) tube or sodium heparin lead free (tan-top) tube • Whole blood collected in: Sodium heparin (royal blue-top) tube or sodium heparin lead free (tan-top) tube • 5x5 mm fresh tumor tissue in transport medium • 5x5 mm tumor tissue in formalin-fixed, paraffin-embedded tissue block


Instructions
Clinical history and reason for referral are required with test order. Prior therapy and transplant history should be provided with test order.
1-3 mL bone marrow in transport medium or in a sodium heparin tube (green top, dark/royal blue top, tan top).
Acceptable samples: 3-5 mL whole blood in a sodium heparin tube (green top, dark/royal blue top, tan top); Formalin fixed paraffin embedded tumor tissue or 5 mm x 5 mm fresh tumor biopsy in transport medium.1-3 mL bone marrow in transport medium or in a sodium heparin tube (green top, dark/royal blue top, tan top).

Note: For each probe set in the panel, 100-300 interphase cells are microscopically analyzed for probe signal patterns indicating rearrangement of the regions: PDGFRA at band 4q12; PDGFRB at band 5q33.1; and FGFR1 at band 8p11-12.
If results are not possible, the test order may be canceled and replaced with a Cytogenetics Communication.


Transport Temperature
Room temperature


Specimen Stability
Specimen viability decreases during transit. Send specimen to testing lab for viability determination. Do not freeze. Do not reject.


Methodology
Fluorescence in situ Hybridization (FISH)

FDA Status
This test was developed and its analytical performance characteristics have been determined by Quest Diagnostics. It has not been cleared or approved by the U.S. Food and Drug Administration. This assay has been validated pursuant to the CLIA regulations and is used for clinical purposes.

Setup Schedule
Set up: Daily; Report available: 5 days


Reference Range
Interpretive Report


Clinical Significance
This FISH panel includes probes that target the PDGFRA (4q12), PDGFRB (5q33.1) and FGFR1 (8p11-12) loci. The probes included in this panel are constructed using the break apart strategy (fusion signal indicates an intact locus). This allows detection of rearrangements of PDGFRA, PDGFRB, and FGFR1 that result from translocations involving various chromosome regions (usually tyrosine kinase coding genes). Fusion of these receptors with a tyrosine kinase coding gene leads to kinase activation.
Rearrangements of PDGFRA, PDGFRB, and FGFR1 are found in a rare group of stem cell myeloid and lymphoid neoplasms that have in common the presence of eosinophilia and the involvement of genes that code for a tyrosine kinase. As such, detection of these rearrangements will help to properly diagnose and follow up of these patients. Furthermore, patients with activated tyrosine kinases are good candidates for tyrosine kinase inhibitors.




The CPT Codes provided in this document are based on AMA guidelines and are for informational purposes only. CPT coding is the sole responsibility of the billing party. Please direct any questions regarding coding to the payor being billed. Any Profile/panel component may be ordered separately. Reflex tests are performed at an additional charge.