Test Overview

Test Methodology

Fluorescence In Situ Hybridization (FISH)

Test Usage

This test detects amplification of the HER2 gene via fluorescence in situ hybridization (FISH) in formalin-fixed, paraffin-embedded breast cancer tissue specimens. FISH is performed using PathVysion (Abbott Molecular, Inc) probes to the HER2 locus (17q11.2-q12) and the chromosome 17 centromere (D17Z1). Results are reported as a HER2:D17Z1 copy number ratio and interpreted according to ASCO/CAP guideline recommendations. HER2 amplification status can be a useful adjunct indicator of prognosis, and can assist in the selection of patients for whom Herceptin (Trastuzumab) treatment is being considered. This test can also rule-out or confirm gene amplification in cases previously evaluated by HER2 immunohistochemistry (IHC), especially those with equivocal (2+) IHC results.

Reference Range*

Interpretive report provided.

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

Test Details

Days Test Performed

Monday - Thursday

Analytic Time

3-10 days

Soft Order Code


MiChart Code




HER-2/neu Amp, Breast CA, FISH
HER2 Amp Breast Cancer, FISH
17q11.2-q12 Probe
FISH for HER-2 Amplification Detection
c-erbB2 Amplification Detection
Herceptin (Trastuzumab) therapy
HER-2/neu by FISH
HER2 Amplification by FISH

+ See More


Molecular Diagnostics

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Specimen Requirements

Offsite Collection Instructions

A formalin-fixed, paraffin-embedded tissue block containing sufficient neoplastic cells is preferred. Unstained slides (3, 4-micron slides) with associated H&E stained slide are also acceptable. Decalcified tissue or other fixatives will be accepted and the assay attempted, however these may result in failed testing due to degraded nucleic acid. Both blocks and slides should be stored at room temperature. The HER2 IHC (immunohistochemistry) slide must also be included with this request. A copy of the HER2 IHC pathology report should accompany this request. Specimens submitted must be fixed between 6 and 72 hours in 10% buffered Formalin.

Normal Volume

Formalin-fixed, paraffin-embedded tissue

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 and the ordering clinician has authorization from the patient permitting MLabs to report the test results to the ordering clinician. Test includes pathologist interpretation of results billed as a separate additional charge. This test is not available without interpretation.

Billing Information

Fee Codes

CPT Code




New York State Approved


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