Wow I just looked on my labs and the LabCorp reference interval is 140 - 415. Mine are normal so I am not sure what the red flag is with HCV meds is.
Here is one of Hector's old posts related to the matter.
He points out that it is the Interferon and not the Riba that causes platelets to decline.
He also points out different doctors have different thresholds for intervention. I am not sure what that intervention there is in terms of a rescue med (other than Interferon dose reduction).
I would not panic yet. I have seen some posts on here where platelets have dropped to 50 and they have managed to finish treatment.
Hang tight and someone who has been down that road is sure to post.