Dr. Bloom Compares HER2 Screening Assays

Kenneth J. Bloom, MD, Chief Medical Officer, Clarient, compares the immunohistochemistry (IHC) and FISH assays for use in routine screening for HER2 expression.

Bloom describes that HER2 testing can be very complicated but that several FDA cleared assays have simplified the process. The approved assays were also used in many of the clinical trials investigating HER2 expression, which further demonstrates their efficacy.

Many of the assays provide similar end results. From a pathologists viewpoint Bloom recommends using the immunohistochemistry (IHC) assay first. The results of the IHC test are equivalent to FISH, however he notes that IHC is quicker, easier to perform, and does not require specialized equipment.

The FISH test requires a darkened room, under high power, and irradiates the lab tech. The IHC assay is more conducive to routine screening because it does not have as many complications.