Maria,
Although both the IHC test and the FISH test both measure HER2 status, there is no correlation between the scores as they both assess a different part of the gene.
Refer to our Tests and Treatments page for more detailed info:
Tests and Treatments
The results of the IHC test would determine if a FISH test would be warranted. Generally if the IHC results are HER2 3+ , a follow up FISH test would be unnecessary. If on the other hand the results were HER2 2+ or
HER2 3, her onc should consider a FISH test.
As she has been recently diagnosed, she may want to consider talking to her onc about the Bayer ELISSA serum test. This will monitor the HER2 levels in her blood and may indicate if the current treatment is effective.
Hugs
Christine