ARUP's Laboratory Test Directory

0049178: HercepTest® with Reflex to HER-2/neu by FISH if 2+

Test Mnemonic: HERCEP2IP
Methodology: Immunohistochemistry

Performed: Mon-Fri

Reported: 1-5 days

Specimen Required:  
Collect: Tumor tissue

Transport: Formalin-fixed, paraffin-embedded tissue block enriched with tumor at 20-25°C. Protect paraffin block from excessive heat. Ship in cooled container during summer months. Include surgical pathology report.

Unacceptable Conditions: Paraffin block with no tumor tissue remaining and samples fixed in formalin substitute.

Stability: Paraffin block: Ambient: Indefinitely; Refrigerated: Acceptable; Frozen: Unacceptable

Reference Interval:
These results are given as 0 to 3+ with the following definitions and interpretations:
 
Grade Interpretation Microscopic Finding
0 Negative No staining is observed or membrane staining is observed in less than 10% of the tumor cells.
1+ Negative Weak but definitive staining of the membrane over 100% of the cytoplasmic circumference in more than 10% of the neoplastic cell population.
2+ Positive Weak but definitive staining of the membrane over 100% of the cytoplasmic circumference in more than 30% of the neoplastic cell population.
3+ Positive Strong positive staining of the membrane over 100% of the cytoplasmic circumference in more than 30% of the neoplastic cell population.
2+ and 3+ reactions with HercepTest® are considered a positive result and indicative of a possible response to Herceptin therapy. 0 and 1+ reactions are considered negative and suggest a lack of response to  Herceptin therapy. It is recommended that a 2+ result be confirmed by FISH testing. FISH results should be considered definitive.

Interpretive Data:
Assay is performed on paraffin-embedded, formalin-fixed tissue. Antibody clone is polyclonal and the detection system is LSAB.

The results of the HercepTest® by DAKO are interpreted in a semi-quantitative manner.

ARUP Laboratories uses the ASCO/CAP criteria for interpretation of HER2 protein expression of 2+ and 3+ positive grades which is based upon staining of the membrane, over 100% of the cytoplasmic circumference, in more than 30% of the neoplastic cell population. 
For more information refer to the ASCO/CAP guidelines found at http://www.jco.org



Note:
If HercepTest result is 2+, then HER-2/neu by FISH will be added.

CPT Code(s):
88360, if reflexed, add 88368 x2

 

 

 
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