Update Type: Test Code Change
Test Updated: 01/17/2024
Test Overview
Test Methodology

Fluorescence In Situ Hybridization (FISH)

Test Usage

This test is used to aid in the diagnosis of difficult solid tumor lesions via fluorescence in situ hybridization (FISH) in formalin-fixed, paraffin-embedded tissue specimens. Three single probe FISH panels are available: 1) probes 9q21 (CDKN2A) and CEP9, 2) 8q24 (MYC), and 3) 3p21 (BAP1) and CEP3. A minimum of 30 cells with visible signals are evaluated for the following parameters: percentage of cells with more than 2 signals per nucleus for 8q24, percentage of cells with fewer signals for 3p21 than for CEP3, percentage of cells with homozygous loss of 3p21, percentage of cells with monosomy loss of 3p21, and percentage of cells with homozygous deletions of 9p21. Nuclei considered tetraploid are excluded from the numerator, but included in the denominator. Homozygous loss of 9p21 or 3p21 are defined by absence of 9p21 or 3p21 and the presence of at least 1 signal for CEP9 or CEP3. A positive result is defined as exceeding the cut-off criteria of the probes.

Reference Range *

Interpretive report provided.

* Reference ranges may change over time. Please refer to the original patient report when evaluating results.

Test Limitations

This test detects copy number aberrations on specific chromosomal targets (3p21, 9p21, and 8q24) documented to have high correlation with malignant lesions, however it will not identify the aberrations in other non-targeted chromosomal segments.

Test Details
Days Set Up
Monday - Friday, 8:30 am - 4:30 pm
Analytic Time

10-14 days

Soft Order Code
Specimen Requirements
Collection Instructions

Three single probe FISH panels are available: 1) probes 9q21 (CDKN2A) and CEP9, 2) 8q24 (MYC), and 3) 3p21 (BAP1) and CEP3. Please specify probe or probes desired. Submit a formalin-fixed, paraffin-embedded block of the tumor tissue or 4 formalin-fixed, paraffin-embedded (FFPE) unstained sections at 4-micron thickness placed on electrostatic-coated slides and one regular H&E obtained as serial sections are required for FISH. Store at room temperature. Cases with less than 30 tumor cells are not suitable for FISH.

Additional Information

By ordering this test the clinician acknowledges that informed consent has been obtained from the patient as required by applicable state or federal laws. Test includes pathologist interpretation of results billed as a separate additional charge. This test is not available without interpretation.

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Fee Code
Pro Fee CPT