ARUP's Laboratory Test Directory

ERBB2 (HER2/neu) (4B5) with Interpretation by Immunohistochemistry, Tissue : 2002218
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Additional Technical Information
  


Mnemonic: 4B5 IP

Methodology: Immunohistochemistry
Performed: Mon-Fri
Reported: 1-5 days
Specimen Required: Collect: Tumor tissue.

Specimen Preparation: Formalin fix (10 percent neutral buffered formalin) and paraffin embed tissue within 30 minutes of removal from patient. Fixative duration: 8-48 hours. Transport tissue block or 5 unstained (3- to 5-micron thick sections), positively charged slides in a tissue transport kit (ARUP supply #47808) available online through eSupply using ARUP Connect ™ or contact ARUP Client Services at (800)522-2787. (Min: 3 slides) If sending precut slides, do not oven bake.

Storage/Transport Temperature: Room temperature or refrigerated. Ship in cooled container during summer months.

Remarks: Pathology report including tissue source and tumor origin must be submitted. Document time from tissue acquisition to fixation and fixation duration on requisition or enter at time of order. IMMUNOHISTOCHEMISTRY ORDERING AND SUBMISSION DETAILS: Submit electronic request. If you do not have electronic ordering capability, use an ARUP Immunohistochemistry form (#32978) with an ARUP client number. For additional technical details, please contact ARUP Client Services at (800) 522-2787.

Unacceptable Conditions: Paraffin block with no tumor tissue remaining. Specimens with fixation delayed for more than 30 minutes. Specimens fixed in any other fixative other than 10 percent neutral buffered formalin. Tissue fixed for less than 8 hours or greater than 48 hours. Cytology specimens fixed in alcohol.

Stability (collection to initiation of testing): Ambient: Indefinite; Refrigerated: Indefinite ; Frozen: Unacceptable
Reference Interval:
Effective May 20, 2013
 
Breast Tumors
Criteria for intensity of cell membrane staining with PATHWAY® HER-2/neu.
Grade Interpretations Microscopic Finding
0 Negative No staining is observed in invasive tumor cells.
1+ Negative Weak, incomplete membrane staining in any proportion of invasive tumor cells, or weak, complete membrane staining in less than 10 percent of cells.
2+ Equivocal Complete membrane staining that is nonuniform or weak but with obvious circumferential distribution in at least 10 percent of cells, or intense complete membrane staining in less than 30 percent of tumor cells.
3+ Positive Uniform intense membrane staining of
more than 30 percent of invasive tumor cells.
3+ reactions with PATHWAY HER2/neu 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, and FISH results should be considered definitive.

Interpretive Data: Refer to report.
CPT Code(s): 88360
Cross References: 4B5