ERBB2 (HER-2/neu) (4B5) Tissue Assay, Paraffin : ARUP Lab Tests

Testing Information

ARUP's Laboratory Test Directory

ERBB2 (HER-2/neu) (4B5) Tissue Assay, Paraffin : 2002218

Mnemonic: 4B5 IP

Methodology:	Immunohistochemistry
Performed:	Mon-Fri
Reported:	1-5 days
Specimen Required:	Collect: Tumor tissue. Specimen Preparation: Formalin fix and paraffin embed specimen. If sending precut slides, do not oven bake. Protect paraffin block and/or slides from excessive heat. 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. IMMUNOHISTOCHEMISTRY ORDERING AND SUBMISSION DETAILS: Submit electronic request. If you do not have electronic ordering capability, use an ARUP Immunohistochemsitry form (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 fixed in formalin substitute. Stability (collection to initiation of testing): Ambient: Indefinite; Refrigerated: Indefinite ; Frozen: Unacceptable

Reference Interval:
Effective August 15, 2011

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% of cells.
2+	Equivocal	Complete membrane staining that is nonuniform or weak but with obvious circumferential distribution in at least 10% of cells, or intense complete membrane staining in less than 30% of tumor cells.
3+	Positive	Uniform intense membrane staining of more than 30% of invasive tumor cells.
3+ reactions with HER2/neu (PATHWAY) 4B5® 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 (ERBB2 (HER-2/neu) (4B5) Tissue Assay, Paraffin)